Control device of construction machine

ABSTRACT

A control apparatus of a construction machine, such as hydraulic excavator, includes arms supported on the construction machine body side, a working member supported by the arms and hydraulic cylinder actuators for operating the arms and the working member, for realizing a smooth variation of an instruction value to the hydraulic cylinder actuators even if the working member is operated suddenly upon starting an operation. In the control apparatus, the arm and working members are operated by driving a control member, a target moving velocity of the working member is set so that the characteristics of the arms and working member upon starting an operation and upon ending an operation as time differentiated are regarded as those before time differentiated, and the actuators are controlled based on the target moving velocity information so that the working member is operated at the target moving velocity.

TECHNICAL FIELD

This invention relates to a construction machine such as a hydraulicexcavator for excavating the ground, and more particularly to a controlapparatus for a construction machine of the type mentioned.

BACKGROUND ART

Generally, a construction machine such as a hydraulic excavator has aconstruction wherein it includes, for example, as shown in FIG. 14, anupper revolving unit 100 with an operator cab (cabin) 600 provided on alower traveling body 500 having caterpillar members 500A, and further, ajoint type arm mechanism composed of a boom 200, a stick 300 and abucket 400 is provided on the upper revolving unit 100.

And, based on extension/contraction displacement information of the boom200, stick 300 and bucket 400 obtained by stroke sensors 210, 220, 230and so forth, the boom 200, stick 300 and bucket 400 can be drivensuitably by hydraulic cylinders 120, 121 and 122, respectively, toperform an excavating operation while keeping the advancing direction ofthe bucket 400 or the posture of the bucket 400 fixed so that control ofthe position and the posture of a working member such as the bucket 400can be performed accurately and stably.

It is to be noted that the hydraulic cylinders 120 to 122 are operatedby operation levers (not shown) normally provided in the operator cab600.

By the way, a semiautomatic control system for such a constructionmachine as described above has been proposed wherein the boom 200, stick300, bucket 400 and so forth are set so that they may perform a sequenceof operations set in advance and the hydraulic cylinders 120, 121 and122 are controlled individually so that their operations set in thismanner may be performed.

Here, as the semiautomatic control mode described above, a bucket anglecontrol mode in which the angle (bucket angle) of the bucket 400 withrespect to a horizontal direction (vertical direction) is always keptfixed even if the stick 300 and the boom 200 are moved, a slope faceexcavation mode (bucket tip linear excavation mode or raking mode) inwhich a tip 112 of the bucket 400 moves linearly, and so forth areavailable.

By the way, in such semiconductor control modes as described above, theoperation levers for controlling the operations of the hydrauliccylinders 120 to 122 function as members for setting target movingvelocities for the stick 300 and the boom 200.

In particular, in a semiautomatic control mode, the moving speeds of thestick 300 and the boom 200 are determined in response to operationamounts of the operation levers.

However, a semiautomatic system applied to a conventional constructionmachine has such various subjects as given below.

(1) If an operator operates an operation lever suddenly upon starting ofworking in a semiautomatic control mode, then control instruction valuesto the hydraulic cylinders 120 to 122 of the boom 200, stick 300 andbucket 400 vary instantly, and it is considered that the load may beapplied suddenly to the hydraulic cylinders 120, 121 and 122. In thisinstance, there is the possibility that the hydraulic cylinder 120, 121or 122 may not operate smoothly but operate while accompanying a lightimpact, vibrations, a shock or the like, and further, there is thepossibility that the accuracy of the locus of the bucket tip positionmay be deteriorated.

In order to eliminate such a situation as described above, it is apossible idea to increase the moving velocity of the bucket tipgradually (ramp up process) or give a smooth velocity variation througha low-pass filter even if an operation lever is operated suddenly.However, in a semiautomatic control mode, since control signals to thehydraulic cylinders are fed-back information obtained by timedifferentiating the cylinder positions, even if such a ramp up processas mentioned above or the like is performed, the instruction values tothe hydraulic cylinders vary discontinuously depending upon the timedifferentiation information of the cylinder positions. Consequently,there still is a subject that the boom, stick or bucket does not operatesmoothly.

(2) In semiautomatic control, where an operation (horizontal levelingoperation or the like) wherein the bucket tip position is moved linearlyis to be performed in a slope face excavation mode, it is supposed thatthe loads to the hydraulic cylinders 120 to 122 during an excavationoperation may be varied by the shape of the ground, the excavationamount or the like, and in such a case, where conventional PID controlis employed, there is the possibility that the degrees of positioningaccuracy of the hydraulic cylinders 120 to 122 or the degree of accuracyof the locus of the bucket tip position may be deteriorated.

Further, where feedback control is performed for the hydraulic cylinders120 to 122, it is supposed that variations of the dynamiccharacteristics of control objects (for example, the hydraulic cylinders120 to 122 or solenoid valves provided in hydraulic circuits) arisingfrom a temperature variation of operating oil have an influence on thecontrol performances of closed loops, resulting in deterioration of thestability of the control system.

In order to eliminate such a situation as described above, the controlgains of the closed loops should be reduced to increase the gain marginsor the phase margins. However, there is a subject that this results indeterioration of the degrees of positioning accuracy of the hydrauliccylinders 120 to 122 or of the degree of accuracy of the locus of thebucket tip position.

(3) Where, in a semiautomatic control mode, the boom 200, stick 300 andbucket 400 are locus controlled (tracking controlled) by feedbackcontrol, since the instruction values to the cylinders 120 to 122 arecalculated based on deviations of the feedback (that is, control errorsbetween input information and output information), it is difficult toreduce the deviations during operation of the cylinders to zero, and asa result, the bucket tip position sometimes exhibits an error from atarget value.

In short, in such feedback control, since actual cylinder positions orcylinder velocities are detected and compared with target cylinderpositions or target cylinder velocities and control is performed so thatthe deviations between them may approach zero, it is difficult toeliminate the deviations completely during control, and there is asubject that a control error is caused thereby.

(4) Where such an operation as to, for example, level the ground (slopeface formation) is to be performed, an operation of linearly moving thetip of the bucket 400 (that is, the stick 300) is required. However,according to the prior art, since the boom 200 and the stick 300 arecontrolled independently of each other by the hydraulic cylinders 120and 121, respectively, it is very difficult to finish a slope face witha high degree of accuracy.

In particular, where the boom 200 and the stick 300 are electricallyfeedback controlled using solenoid valves or the like as describedabove, if the corresponding hydraulic cylinders 120 and 121 arecontrolled independently of each other, respectively, then even if therespective feedback control deviations are small, the control deviationscannot be ignored depending upon the positions (postures) of the boom200 and the stick 300, and an error from a target tip position (controltarget value) of the bucket 400 sometimes becomes very large.

For example, if control of the boom 200 is delayed with respect to thestick 300 due to the control deviations described above when the bucket400 is at a position at which a slope face is to be formed subsequently,then the tip of the bucket 400 will bite into the ground, but if controlof the stick 300 is delayed with respect to the boom 200, then thebucket 400 will operate while it remains floating in the air.

In this manner, there is a subject that, if the boom 200 and the stick300 are individually controlled fully independently of each other, thenit is very difficult to operate the boom 200 and the stick 300 whilemaintaining control target values.

(5) Where an operation of moving the tip of the bucket 400 linearly(called bucket tip linear excavation mode) such as horizontal levelingof the ground (slope face formation) is required, with the conventionalcontrol apparatus for a hydraulic excavator, the operation is realizedby feedback controlling the boom 200 (hydraulic cylinder 120) and thestick 300 (hydraulic cylinder 121) electrically independently of eachother. However, since the hydraulic cylinders 120 and 121 are feedbackcontrolled independently of each other based on control target valuesobtained from a target bucket tip position, for example, when it istried to pull the stick 300 from a condition wherein the bucket 400 ispositioned far from the construction machine body 100 toward theconstruction machine body 100 side to linearly move the tip of thebucket 400, if the position deviation of the boom 200 is small (thedelay is little) and the position deviation of the stick 300 is large(the delay is much), then the actual tip position of the bucket 400 isdisplaced upwardly from the target position (target slope face). As aresult, there is a subject that the finish accuracy of the slope face isdeteriorated very much.

(6) Where an operation (raking) of linearly moving the tip of the bucket400 as in, for example, a horizontal leveling operation is performedautomatically by a controller, solenoid valves (control valvemechanisms) in the hydraulic circuits for supplying and dischargingoperating oil to and from the hydraulic cylinders 120, 121 and 122 areelectrically PID feedback controlled to control extension/contractionoperations of the hydraulic cylinders 120, 121 and 122 to control thepostures of the boom 200, stick 300 and bucket 400. However, in thehydraulic circuits which control the extension/contraction operations ofthe hydraulic cylinders 120, 121 and 122, operating oil pressures areproduced by pumps which are driven by an engine (prime mover), and ifthe rotational speed of the engine is varied by an external load or thelike then, then also the rotational speeds of the pumps are varied bythe variation, resulting in variation of the discharges (deliverycapacities) of the pumps. Consequently, even if the instruction values(electric currents) to the solenoid valves are equal, theextension/contraction velocities of the hydraulic cylinders 120, 121 and122 are varied. As a result, the posture control accuracy of the bucket400 is deteriorated, and the finish accuracy of a horizontally leveledface or the like by the bucket 400 is deteriorated.

Thus, it is a possible idea to use, in order to cope with such arotational speed variation of the engine as described above, a pump ofthe variable discharge type (variable delivery pressure type, variablecapacity type) for the pumps and adjust the tilt angles of the pumps tocontrol the pumps so that the delivery capacities of the pumps may befixed even if the rotational speed of the engine (that is, therotational speeds of the pumps) varies. However, since such tilt anglecontrol is slow in response, there is a subject that target cylinderextension/contraction velocities cannot be secured and deterioration ofthe finish accuracy cannot be avoided.

(7) With the prior art wherein a circuit of the open center type is usedfor the hydraulic circuits, for example, where the excavation load isextremely heavy, as the load increases, the oil pressures of the boom200 (hydraulic cylinder 120) and the stick 300 (hydraulic cylinder 121)rise and the extension/contraction displacement velocities of thehydraulic cylinders 120 and 121 drop, and finally, the operations of theboom 200 and the stick 300 (that is, the operation of the bucket tip)sometimes stop.

In this instance, with the PID feedback control system, since thevelocity information (P) of the bucket tip becomes equal to zero and theposition information (D) is fixed to a value equal to that upon stoppingof the stick, they have no influence on target velocities for theextension/contraction displacement velocities of the hydraulic cylinders120 and 121 which are based on the information (proportional operationfactors), but since I (an integration factor) is involved in the controlsystem, the target velocities of the hydraulic cylinders 120 and 121resultantly continue to increase.

Accordingly, if, for example, a rock under excavation which has beencaught by the bucket tip breaks in this condition and the load isremoved suddenly from the boom 200 and the stick 300, then the hydrauliccylinders 121 and 122 will suddenly begin to move at velocities muchhigher than their target velocities. As a result, there is a subjectthat the finish accuracy of an excavation operation is deterioratedsignificantly.

(8) Where such control that the angle (bucket angle) of the bucket 400with respect to the horizontal direction (vertical direction) is alwayskept fixed even if the boom 200 and the stick 300 are moved such aswhere excavated sand and earth or the like are conveyed while they areaccommodated in the bucket 400, with the PID feedback control system forthe bucket 400 (hydraulic cylinder 122), if the deviation between theactual bucket angle and the target bucket angle becomes large duringoperation of the boom 200 and/or the stick 300, then the instructionvalue (control target value) to the hydraulic cylinder 122 is increasedto decrease the deviation by an action of the I (integration factor) ofthe P (proportion factor), I (integration factor) and D (differentiationfactor). However, when the operation levers (operation members) 6 and 8for the boom 200, stick 300 and bucket 400 are moved to their neutralpositions (inoperative positions) to stop the bucket 400, since theinstruction value to the hydraulic cylinder 122 is not reduced to zeroimmediately due to an accumulation amount of the I (integration factor)till the stopping time. Consequently, there is a subject that, even ifthe operation levers 6 and 8 are moved to the inoperative positions, thebucket 400 does not stop immediately and an overshoot occurs, resultingin deterioration of the control accuracy.

The present invention has been made in view of such various subjects asdescribed above, and it is an object of the present invention to providea control apparatus for a construction machine having a semiautomaticcontrol mode which achieves further augmentation of functions.

DISCLOSURE OF THE INVENTION

To this end, according to the present invention, a control apparatus fora construction machine wherein arm members are supported for rockingmovement on a construction machine body side and a working member issupported for rocking movement at an end portion of the arm members andthe rocking movements of the arm members and the working member areperformed individually by extension/contraction operations of cylindertype actuators is characterized in that it comprises operation leversfor operating the arm members and the working member, target movingvelocity setting means for setting a target moving velocity of theworking member so that a target moving velocity characteristic uponstarting of operation by the operation levers may exhibit acharacteristic of the same type even if the target moving velocitycharacteristic is time differentiated, and control means for receivinginformation of the target moving velocity set by the target movingvelocity setting means as an input and controlling the actuators so thatthe working member may exhibit the target moving velocity.

With such a construction as described above, there is an advantage that,even if an operator operates the operation levers suddenly upon startingof operation, the arm members and the working member can be operatedsmoothly.

Preferably, the target moving velocity characteristic upon starting ofthe operation is set to a cosine wave characteristic. By this, wheninformation obtained by time differentiation of the positions of theactuators is fed back to the control means to set control signals, thefed back time differentiation information and the target moving velocitycharacteristic upon starting of the operation have characteristics ofthe same type and the cosine wave characteristic has a continuous curve,and consequently, the control signals to be outputted are suppressedfrom varying instantly suddenly. Accordingly, there is an advantagethat, upon starting of operation, operations of the cylinder typeactuators can be performed smoothly. Further, by setting the targetmoving velocity characteristic to the cosine wave characteristic, thereis another advantage that control superior in operation responsibilityupon starting of operation can be realized.

Where the target moving velocity characteristic upon ending of theoperation by the working member is set so that it may exhibit acharacteristic of the same type even if the target moving velocitycharacteristic is time differentiated, also when the operator operatesthe operation levers suddenly not only upon starting of operation butalso upon ending of the operation, the arm members and the workingmember can be operated smoothly.

Where the target moving velocity characteristic upon ending of theoperation is set to a cosine wave characteristic, control which issuperior in operation responsibility also upon ending of the operationcan be realized.

Preferably, the target moving velocity setting means includes a targetmoving velocity outputting section for outputting first target movingvelocity data corresponding to positions of the operation levers, astorage section in which second target moving velocity data with whichthe target moving velocity characteristics upon starting of theoperation and upon ending of the operation exhibit characteristics ofthe same types even if the target moving velocity characteristics aretime differentiated are stored, and a comparison section for comparingthe data of the storage section and the data of the target movingvelocity outputting section and outputting a lower one of the data astarget moving velocity information.

Where the control apparatus for a construction machine is constructed insuch a manner as just described, there is an advantage that, when askilled operator operates the operation levers in a condition moreappropriate than by control of the cylinder type actuators by thestorage section, the operation by the operator is given priority tocontrol the operation of the cylinder type actuators.

Further, according to the present invention, a control apparatus for aconstruction machine wherein arm members are supported for rockingmovement on a construction machine body side and a working member issupported for rocking movement at an end portion of the arm members andthe rocking movements of the arm members and the working member areperformed individually by extension/contraction operations of cylindertype actuators is characterized in that it comprises target valuesetting means for setting target operation information of the arm memberwith the working member in response to a position of an operationmember, detection means having at least operation information detectionmeans for detecting operation information of the arm member with theworking member and operation condition detection means for detecting anoperation condition of the construction machine, and control means of avariable control parameter type for receiving a detection result fromthe operation information detection means and the target operationinformation set by the target value setting means as inputs andcontrolling the actuators so that the arm member with the working membermay exhibit a target operation condition, and a control parameterscheduler capable of varying the control parameter in response to theoperation condition of the construction machine detected by theoperation condition detection means is provided in the control means.

Where such a construction as just described is employed, there is anadvantage that the stability in control and the accuracy in position ofthe working member can be augmented.

The control means may include feedback loop type compensation meanshaving a variable control parameter and feedforward type compensationmeans having a variable control parameter. Where such a construction asjust described is employed, there is an advantage that controldeviations can be reduced and velocity instruction values can beoutputted irrespective of the magnitudes of position deviations fromtarget velocities of the actuators.

Where the control parameter scheduler is constructed so as to allow thecontrol parameter to be varied in response to positions of theactuators, the control parameter can be corrected in response to theoperation posture of the construction machine, and there is an advantagethat augmentation of the stability of controlling systems andaugmentation of the accuracy of the position of the working member canbe achieved.

Meanwhile, where the control parameter scheduler is constructed so as toallow the control parameter to be varied in response to loads to theactuators, correction of the control parameter can be performed inresponse to the operation load to the construction machine, and there isan advantage that, similarly as described above, augmentation of thestability of controlling systems and augmentation of the accuracy of theposition of the working member can be achieved.

On the other hand, where the control parameter scheduler is constructedso as to allow the control parameter to be varied in response to atemperature relating to the actuators, the variation of the temperaturerelating to the actuators can be compensated for, and there still is anadvantage that augmentation of the stability of controlling systems andaugmentation of the accuracy of the position of the working member canbe achieved.

Preferably, for the temperature relating to the actuators, a temperatureof operating oil or a temperature of controlling oil of the actuators isused. In this instance, upon operation, a variation of the temperatureof the operating oil or controlling oil which is comparatively likely tovary upon operation can be compensated for, and there still is anadvantage that augmentation of the stability of controlling systems andaugmentation of the accuracy of the position of the working member canbe achieved.

Further, according to the present invention, a control apparatus for aconstruction machine wherein arm members are supported for rockingmovement on a construction machine body side and a working member issupported for rocking movement at an end portion of the arm members andthe rocking movement of the arm member with the working member isperformed individually by extension/contraction operations of cylindertype actuators is characterized in that it comprises target valuesetting means for setting target operation information of the arm memberwith the working member in response to a position of an operation lever,operation information detection means for detecting operationinformation of the arm member with the working member, control means forreceiving a detection result of the operation information detectionmeans and the target operation information set by the target valuesetting means as inputs and controlling the actuators so that the armmember with the working member may exhibit a target operation condition,and correction information storage means for storing correctioninformation for correcting the target operation information, and thecontrol means is constructed so as to control the actuators usingcorrection target operation information corrected with the correctioninformation from the correction information storage means so that thearm member with the working member may exhibit the target operationcondition.

Where such a construction as described above is employed, there is anadvantage that a deviation between target operation information and anactual operation can be eliminated to the utmost and the degrees ofcontrol accuracy of the actuators can be augmented. In particular, bytaking correction information obtained from the correction informationstorage means into consideration of target operation information set bythe target value setting means, the degrees of accuracy of the positioncontrol and the velocity control of the actuators can be improvedremarkably. Further, the present apparatus is advantageous also in thatit requires little increase in cost or little increase in weight due toits simple construction that the correction information storage sectionis provided.

The correction information storage means may be constructed so as tocause the arm member with the working member to perform a predeterminedoperation to collect and store the correction information.

Where such a construction is employed, there is an advantage thatdeviations appearing between target operation information of theactuators set by the target value setting means and actual operationinformation of the actuators can be obtained by simulation. Further,since the target value setting means is corrected using the deviations,the deviations between the target operation information and the actualoperation information can be eliminated to the utmost and the accuracyin operation control of the arm member with the working member can befurther augmented.

Further, the correction information storage means may be constructed soas to store correction information which is different for differentoperation modes of the arm member with the working member, and thecontrol means may be constructed so as to control the actuators usingthe correction target operation information corrected with thecorrection information obtained in response to an operation mode of thearm member with the working member so that the arm member with theworking member may exhibit the target operation condition.

In this instance, there is an advantage that a deviation between targetoperation information and actual operation information can be updatedfor each of the operation modes and, in whichever operation mode controlis performed, the deviation between the target operation information andthe actual operation information can be eliminated to the utmost therebyto augment the control accuracy.

Further, according to the present invention, a control apparatus for aconstruction machine wherein, when at least one pair of arm membersconnected for pivotal motion to each other and composing a joint typearm mechanism provided on a construction machine body are driven bycylinder type actuators, the cylinder type actuators are feedbackcontrolled based on detected posture information of the arm members sothat the arm members may individually assume predetermined postures ischaracterized in that the pair of arm members are controlled in amutually associated relationship with each other such that a controltarget value of a controlling system of each of the arm members may becontrolled based on feedback deviation information of a controllingsystem of the other arm member than the self arm member.

In the control apparatus having such a construction as described above,when the pair of arm members mentioned above are controlledindividually, since the arm members are controlled in a mutuallyassociated relationship with each other such that the control targetvalue of the controlling system of each of the arm members may becorrected based on the feedback deviation information of the controllingsystem of the other arm member than the self arm member, the arm memberscan be operated in an ideal condition in which no feedback deviationinformation is involved.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a joint type arm mechanism having at leastone pair of arm members having one end portion pivotally mounted on theconstruction machine body and having a working member on the other endside and connected to each other by a joint part, a cylinder typeactuator mechanism having a plurality of cylinder type actuators forperforming extension/contraction operations to actuate the armmechanism, posture detection means for detecting posture information ofthe arm members, and control means for controlling the cylinder typeactuators based on a detection result detected by the posture detectionmeans so that the arm members may exhibit predetermined postures, thecontrol means including a first controlling system for feedbackcontrolling the first cylinder type actuator for one arm member of thepair of arm members, a second controlling system for feedbackcontrolling the second cylinder type actuator for the other arm memberof the pair of arm members, a first correction controlling system forcorrecting a control target value of the first controlling system basedon feedback deviation information of the second controlling system, anda second correction controlling system for correcting a control targetvalue of the second controlling system based on feedback deviationinformation of the first correction controlling system.

In the control apparatus of the present invention constructed in such amanner as described above, since, when the control means (first andsecond controlling systems) controls the (first and second) actuatorsbased on the detection result detected by the posture detection means sothat the arm members may assume predetermined postures, the first orsecond controlling system corrects the control target value of the self(first or second) controlling system based on the feedback deviationinformation of the second or first controlling system, correction of thecontrol target values mutually taking the control conditions of theactuators into consideration is performed, and the arm members operatein an ideal condition in which no feedback deviation information isinvolved.

It is to be noted that preferably the posture detection means isconstructed as extension/contraction displacement detection means fordetecting extension/contraction displacement information of the cylindertype actuators. By this, in the present control apparatus, postureinformation of the arm members can be detected simply and convenientlyby detecting extension/contraction displacement information of thecylinder type actuators.

Meanwhile, the control apparatus for a construction machine may beconstructed such that the first correction controlling system includes afirst correction value generation section for generating a firstcorrection value for correcting the control target value of the firstcontrolling system from the feedback deviation information of the secondcontrolling system, and the second correction controlling systemincludes a second correction value generation section for generating asecond correction value for correcting the control target value of thesecond controlling system from the feedback deviation information of thefirst controlling system.

Where the control apparatus for a construction machine is constructed insuch a manner as just described, by the simple construction that thefirst correction value generation section is provided in the firstcorrection controlling system and the second correction value generationsection is provided in the second correction controlling system, thefirst correction value for correcting the control target value of thefirst controlling system and the second correction value for correctingthe control target value of the second controlling system can begenerated to effect correction of the control target values withcertainty.

Further, the first correction controlling system may include a firstweight coefficient addition section for adding a first weightcoefficient to the first correction value. By this, in the firstcorrection controlling system, the first correction value for correctingthe control target value of the first controlling system can be variedwhen necessary, and correction of the control target value can beperformed flexibly.

On the other hand, the second correction controlling system may includea second weight coefficient addition section for adding a second weightcoefficient to the second correction value. By this, also in the secondcorrection controlling system, the second correction value forcorrecting the control target value of the second controlling system canbe varied when necessary, and correction of the control target value canbe performed flexibly.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a boom connected at one end thereof forpivotal motion to the construction machine body, a stick connected atone end thereof for pivotal motion to the boom by a joint part andhaving a bucket, which is capable of excavating the ground at a tipthereof and accommodating sand and earth therein, mounted for pivotalmotion at the other end thereof, a boom hydraulic cylinder interposedbetween the construction machine body and the boom for pivoting the boomwith respect to the construction machine body by expanding orcontracting a distance between end portions thereof, a stick hydrauliccylinder interposed between the boom and the stick for pivoting thestick with respect to the boom by expanding or contracting a distancebetween end portions thereof, boom posture detection means for detectingposture information of the boom, stick posture detection means fordetecting posture information of the stick, a boom controlling systemfor feedback controlling the boom hydraulic cylinder based on adetection result of the boom posture detection means, a stickcontrolling system for feedback controlling the stick hydraulic cylinderbased on a detection result of the stick posture detection means, a boomcorrection controlling system for correcting a control target value ofthe boom controlling system based on feedback deviation information ofthe stick controlling system, and a stick correction controlling systemfor correcting a control target value of the stick controlling systembased on feedback deviation information of the boom controlling system.

In the control apparatus for a construction machine of the presentinvention constructed in such a manner as described above, when theboom/stick controlling systems feedback control the boom/stick hydrauliccylinders based on detection results detected by the correspondingboom/stick posture detection means, since the boom/stick correctioncontrolling systems correct the control target values of the selfcontrolling systems based on feedback deviation information of thestick/boom controlling systems, respectively, correction of the controltarget values mutually taking the control conditions of the hydrauliccylinders into consideration is normally performed, and the boom and thestick individually operate in an ideal condition wherein no feedbackdeviation information is involved.

Preferably, the boom posture detection means is constructed as boomhydraulic cylinder extension/contraction displacement detection meansfor detecting extension/contraction displacement information of the boomhydraulic cylinder, and the stick posture detection means is constructedas stick hydraulic cylinder extension/contraction displacement detectionmeans for detecting extension/contraction displacement information ofthe stick hydraulic cylinder.

By this, in the present control apparatus, posture information of theboom/stick can be detected simply and conveniently by detectingextension/contraction displacement information of the boom/stickhydraulic cylinders.

Further, the boom correction controlling system may include a boomcorrection value generation section for generating a boom correctionvalue for correcting the control target value of the boom controllingsystem from the feedback deviation information of the stick controllingsystem, and the stick correction controlling system may include a stickcorrection value generation section for generating a stick correctionvalue for correcting the control target value of the stick controllingsystem from the feedback deviation information of the boom controllingsystem.

And, by such a simple construction as just described, a boom correctionvalue for correcting the control target value of the boom controllingsystem and a stick correction value for correcting the control targetvalue of the stick controlling system can be generated to effectcorrection of the control target values with certainty.

Further, the boom correction controlling system may include a boomweight coefficient addition section for adding a boom weight coefficientto the boom correction value. In this instance, in the boom correctioncontrolling system, the boom correction value for correcting the controltarget value of the boom controlling system can be varied whennecessary, and correction of the control target value can be performedflexibly.

Furthermore, the stick correction controlling system may include a stickweight coefficient addition section for adding a stick weightcoefficient to the stick correction value. By this, also in the stickcorrection controlling system, the stick correction value for correctingthe control target value of the stick controlling system can be variedwhen necessary, and correction of the control target value can beperformed flexibly.

Further, according to the present invention, a control apparatus for aconstruction machine wherein, when at least one pair of arm membersconnected for pivotal motion to each other and composing a joint typearm mechanism provided on a construction machine body are actuated bycylinder type actuators, the cylinder type actuators are controlledbased on a calculation control target value obtained from operationposition information of operation members so that the arm members mayassume predetermined postures, is characterized in that, from actualposture information of a self one and the other of the arm members, anactual control target value of a controlling system for the self armmember of the arm members is determined and a composite control targetvalue is determined from the actual control target value and thecalculation control target value, and the hydraulic type cylinder iscontrolled based on the composite control target value so that a desiredone arm member of the pair of arm members may assume a predeterminedposture.

In the control apparatus for a construction machine of the presentinvention having such a construction as just described, since theposture of the desired arm member is controlled based on a target value(composite control target value) obtained by composition of an idealcalculation control target value obtained by calculation from theoperation position information of the arm mechanism operation members(an ideal target value for controlling the arm members to targetpostures) and an actual control target value determined from actualpostures of the arm members taking the actual postures intoconsideration, the postures of the arm members can always be controlledtaking actual postures of the arm members into considerationautomatically.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a joint type arm mechanism having at leastone pair of arm members having one end portion pivotally mounted on theconstruction machine body and having a working member on the other endside and connected to each other by a joint part, a cylinder typeactuator mechanism having a plurality of cylinder type actuators foractuating the arm mechanism by performing extension/contractionoperations, calculation control target value setting means fordetermining a calculation target control value from operation positioninformation of an arm mechanism operation member, and control means forcontrolling the cylinder type actuators based on the calculation controltarget value obtained by the calculation control target value settingmeans so that the arm members may individually assume predeterminedpostures, the control means including actual control target valuecalculation means for determining, for a desired one arm member of thepair of arm members, an actual control target value for a controllingsystem for the self arm member from actual posture information of theself and the other one of the arm members, composite control targetvalue calculation means for determining a composite control target valuefrom the actual control target value obtained by the actual controltarget value calculation means and the calculation control target valueobtained by the calculation control target value setting means, and acontrolling system for controlling the cylinder type actuator based onthe composite control target value obtained by the composite controltarget value calculation means so that the desired one arm member mayassume a predetermined posture.

In the construction machine for a construction machine of the presentinvention having such a construction as just described, since thecylinder type actuator for the desired arm member is controlled based ona target value (composite control target value) obtained by compositionof an ideal calculation control target value obtained by calculationfrom the operation position information of the arm mechanism operationmembers (an ideal target value for controlling the arm members to targetpostures) and an actual control target value determined from actualpostures of the arm members taking the actual postures intoconsideration, the postures of the arm members can always be controlledsimply and conveniently taking actual postures of the arm members intoconsideration automatically.

Here, if the controlling system described above is constructed so as tofeedback control the cylinder type actuators based on the compositecontrol target value obtained by the composite control target valuecalculation means and the posture information of the arm membersdetected by the arm member posture detection means so that the armmembers may individually assume predetermined postures, then the controldescribed above can be realized with a simple construction.

Further, if the arm member posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the cylinder typeactuators, then actual postures of the arm members can be detectedsimply, conveniently and accurately.

Furthermore, if the composite control target value calculation means isconstructed so as to add predetermined weight information to the actualcontrol target value and the calculation control target value todetermine the composite control target value, then to which one of theactual target control value and the calculation control target valueimportance should be attached to effect control can be changed inresponse to a situation (actual postures of the arm members).

Further, where fluid pressure circuits for the cylinder type actuatorsare open center type circuits with which extension/contractiondisplacement velocities of the cylinder type actuators depend upon aload acting upon the cylinder type actuators, since theextension/contraction displacement velocities of the cylinder typeactuators vary in response to the load acting upon the cylinder typeactuators, it is particularly effective to control the cylinder typeactuators taking the actual postures of the arm members intoconsideration as described above.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a boom connected at one end thereof forpivotal motion to the construction machine body, a stick connected atone end thereof for pivotal motion to the boom by a joint part andhaving a bucket, which is capable of excavating the ground at a tipthereof and accommodating sand and earth therein, mounted for pivotalmotion at the other end thereof, a boom hydraulic cylinder interposedbetween the construction machine body and the boom for pivoting the boomwith respect to the construction machine body by expanding orcontracting a distance between end portions thereof, a stick hydrauliccylinder interposed between the boom and the stick for pivoting thestick with respect to the boom by expanding or contracting a distancebetween end portions thereof, stick control target value setting meansfor determining a stick control target value for stick control fromoperation position information of an arm mechanism operation member, astick controlling system for controlling the stick hydraulic cylinderbased on the stick control target value obtained by the stick controltarget value setting means, boom control target value setting means fordetermining a boom control target value for boom control from operationposition information of the arm mechanism operation member, actual boomcontrol target value calculation means for determining an actual boomcontrol target value for boom control from actual posture information ofthe boom and the stick, composite boom control target value calculationmeans for determining a composite boom control target value from theactual boom control target value obtained by the actual boom controltarget value calculation means and the boom control target valueobtained by the boom control target value setting means, and a boomcontrolling system for controlling the boom hydraulic cylinder based onthe composite boom control target value obtained by the composite boomcontrol target value calculation means so that the boom may assume apredetermined posture.

In the control apparatus for a construction machine of the presentinvention having such a construction as described above, since the boomhydraulic cylinder is controlled based on a target value (composite boomcontrol target value) obtained by composition of an ideal stick controltarget value and boom control target value obtained by calculation fromthe operation position information of the arm mechanism operationmembers (ideal target values for controlling the stick and the boom torespective target postures) and a target value (actual boom controltarget value) determined from actual postures of the stick and the boomtaking the actual postures into consideration, the posture of the boomcan always be controlled simply and conveniently taking actual posturesof the boom and the stick into consideration automatically.

Here, if the stick controlling system is constructed so as to feedbackcontrol the stick hydraulic cylinder based on the stick control targetvalue and the posture information of the stick detected by the stickposture detection means, and the boom controlling system is constructedso as to feedback control the boom hydraulic cylinder based on thecomposite boom control target value and the posture information of theboom detected by the boom posture detection means so that the boom mayassume a predetermined posture, then the control described above can berealized with a simple construction.

Further, if the stick posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the stick hydrauliccylinder, and the boom posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the boom hydrauliccylinder, then the actual postures of the stick and the boom can bedetected simply, conveniently and accurately.

Furthermore, if the actual boom control target value calculation meansincludes an actual bucket tip position calculation section forcalculating tip position information of the bucket from the actualposture information of the boom and the stick, and an actual boomcontrol target value calculation section for determining the actual boomcontrol target value from the tip position information of the bucketobtained by the actual bucket tip position calculation section, then theboom (boom hydraulic cylinder) can be controlled so that the tipposition of the bucket may assume a predetermined posture (position).

Further, if the composite boom control target value calculation means isconstructed so as to add predetermined weight information to the actualboom control target value and the boom control target value to determinethe composite boom control target value, then to which one of the actualboom control target value and the boom control target value importanceshould be attached to effect control can be changed in response to asituation (actual postures of the boom and stick).

It is to be noted that, if the weight information added by the compositeboom control target value calculation means is set so as to assume avalue higher than 0 but lower than 1, then to which one of the actualboom control target value and the boom control target value importanceshould be attached can be changed simply and conveniently.

Further, if the composite boom control target value calculation means isconstructed so as to add a first weight coefficient to the boom controltarget value and add a second weight coefficient to the actual boomcontrol target value to determine the composite boom control targetvalue, then the weight coefficients of the target values canindividually be varied in response to actual postures of the boom andthe stick.

In this instance, if the first weight coefficient and the second weightcoefficient added by the composite boom control target value calculationmeans are set so as to both assume values higher than 0 but lower than1, then the target values can be varied simply and conveniently.

Further, in this instance, if the first weight coefficient and thesecond weight coefficient are set so that the sum thereof may be 1, thento which one of the actual boom control target value and the boomcontrol target value importance should be attached can be set only bysetting one of the weight coefficients.

It is to be noted that, if the first weight coefficient added by thecomposite boom control target value calculation means is set so as todecrease as an extension amount of the stick hydraulic cylinderincreases, then control wherein increasing importance is attached to theactual boom control target value as the extension amount of the stickhydraulic cylinder increases is performed.

Further, where fluid pressure circuits for the boom hydraulic cylinderand stick hydraulic cylinder are open center type circuits with whichextension/contraction displacement velocities of the cylinders dependupon a load acting upon the cylinders, since the extension/contractiondisplacement velocities of the cylinder type actuators vary in responseto the load acting upon the hydraulic cylinders, it is particularlyeffective to control the hydraulic cylinders taking the actual posturesof the boom and the stick into consideration as described above.

Further, according to the present invention, a control apparatus for aconstruction machine wherein, when a joint type arm mechanism providedon a construction machine body is actuated by cylinder type actuatorswhich are connected to fluid pressure circuits having at least pumpsdriven by a prime mover and control valve mechanism and operate withdelivery pressures from the pumps, control signals are supplied to thecontrol valve mechanism based on detected posture information of thejoint type arm mechanism to control the cylinder type actuators so thatthe joint type arm mechanism may assume a predetermined posture, ischaracterized in that, if a delivery capacity variation factor of thepumps in the prime mover is detected, then the control signals arecorrected in response to the delivery capacity variation factor.

In the control apparatus for a construction machine described above,since, if a delivery capacity variation factor of the pumps in the primemover is detected, then the control signals to the control valvemechanism are corrected in response to the delivery capacity variationfactor, even if a delivery capacity variation factor of the pumpsoccurs, control of the control valve mechanism is performed in responseto the variation and the cylinder type actuators are controlled rapidlyagainst the variation, and consequently, the operation velocitiesthereof can be secured.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a joint type arm mechanism having at leastone pair of arm members having one end portion pivotally mounted on theconstruction machine body and having a working member on the other endside and connected to each other by a joint part, a cylinder typeactuator mechanism having a plurality of cylinder type actuators foractuating the arm mechanism by performing extension/contractionoperations, fluid pressure circuits at least having pumps driven by aprime mover and control valve mechanism for supplying and dischargingoperating fluid to and from the cylinder type actuator mechanism tocause the cylinder type actuators of the cylinder type actuatormechanism to effect extension/contraction operations, posture detectionmeans for detecting posture information of the arm members, controlmeans for supplying control signals to the control valve mechanism basedon a detection result detected by the posture detection means to controlthe cylinder type actuators so that the arm members may individuallyassume predetermined postures, and variation factor detection means fordetecting a delivery capacity variation factor of the pumps in the primemover, the control means including correction means for correcting, whena delivery capacity variation factor of the pumps is detected by thevariation factor detection means, the control signals in response to thedelivery capacity variation factor.

In this instance, the control apparatus for a construction machine maybe constructed such that the prime mover is constructed as a rotationaloutput type prime mover, and the variation factor detection means isconstructed as means for detecting rotational speed information of theprime mover, and besides the correction means corrects, when it isdetected by the variation factor detection means that the rotationalspeed information of the prime mover has varied, the control signals inresponse to the variation.

Further, the correction means may include reference rotational speedsetting means for setting reference rotational speed information of theprime mover, deviation calculation means for calculating a deviationbetween the reference rotational speed information set by the referencerotational speed setting means and actual rotational speed informationof the prime mover detected by the variation factor detection means, andcorrection information calculation means for calculating correctioninformation for correcting the control signals in response to thedeviation obtained by the deviation calculation means.

Furthermore, the correction information calculation means may includestorage means for storing correction information for correcting thecontrol signals in response to the deviation obtained by the deviationcalculation means.

In the control apparatus for a construction machine, if a deliverycapacity variation factor of the pumps in the prime mover is detected bythe variation factor detection means, then since the control signalsfrom the control means to the control valve mechanism are corrected inresponse to the delivery capacity variation factor by the correctionmeans, even if a delivery capacity variation factor of the pumps occurs,control of the control valve mechanism is performed in response to thevariation and the cylinder type actuators are controlled rapidly againstthe variation, and consequently, the operation velocities thereof can besecured.

In this instance, if the prime mover is a rotational output type primemover, then by detecting rotational speed information of the prime moverby the variation factor detection means, a variation of rotational speedinformation of the prime mover is detected as a delivery capacityvariation factor of the pumps in the prime mover, and the correctionmeans corrects the control signals in response to the variation of therotational speed information of the prime mover.

Further, in the correction means, a deviation between the referencerotational speed information set by the reference rotational speedsetting means and actual rotational speed information of the prime moverdetected by the variation factor detection means is calculated by thedeviation calculation means, and correction information for correctingthe control signals is calculated in response to the deviation by thecorrection information calculation means.

Furthermore, where correction information for correcting the controlsignals in response to a deviation obtained by the deviation calculationmeans is stored in the storage means in advance, correction informationcorresponding to a deviation obtained by the deviation calculation meanscan be read out from the storage means to effect calculation ofcorrection information.

Further, according to the present invention, a control apparatus for aconstruction machine wherein, when arm members which compose a jointtype arm mechanism provided on a construction machine body are actuatedby cylinder type actuators whose extension/contraction displacementvelocities vary in response to a load thereto, the cylinder typeactuators are controlled based on a control target value so that thejoint type arm mechanism may assume a predetermined posture, ischaracterized in that the control apparatus is constructed so as toreduce, when the load to the actuators is higher than a predeterminedvalue, the control target value to reduce the extension/contractiondisplacement velocities of the cylinder type actuators.

Further, according to the present invention, a control apparatus for aconstruction machine, characterized in that it comprises a constructionmachine body, a joint type arm mechanism having at least one pair of armmembers having one end portion pivotally mounted on the constructionmachine body and having a working member on the other end side andconnected to each other by a joint part, a cylinder type actuatormechanism having a plurality of cylinder type actuators for actuatingthe arm mechanism by effecting extension/contraction operations suchthat extension/contraction displacement velocities may vary dependingupon a load, control target value setting means for calculating acontrol target value from operation position information of operationmembers, control means for controlling the cylinder type actuators basedon the control target value obtained by the target value setting meansso that the arm members may individually assume predetermined postures,and actuator load detection means for detecting load conditions to thecylinder type actuators, the control means having first correction meansfor reducing, when the load to the cylinder type actuators detected bythe actuator load detection means is higher than a predetermined value,the control target value set by the target value setting means inresponse to the load condition of the cylinder type actuators to lowerthe extension/contraction displacement velocity by the cylinder typeactuators.

With such a construction as described above, since, when the load to thecylinder type actuators for actuating the arm members is higher than thepredetermined value, the control target value is reduced to control theactuators so that the extension/contraction displacement velocities ofthem may be reduced, even if the load to the actuators is removed(reduced) suddenly, the extension displacements of them can becontrolled very smoothly without being varied suddenly. Consequently,the finish accuracy in a desired construction operation can be augmentedsignificantly.

Further, the control apparatus for a construction machine may beconstructed such that it comprises posture detection means for detectingthe posture information of the arm members, and the control meansfeedback controls the cylinder type actuators based on the controltarget value obtained by the target value setting means and the postureinformation of the arm members detected by the posture detection meansso that the arm members may individually assume predetermined postures.

With such a construction as just described, since the arm members can becontrolled so as to assume predetermined postures with a higher degreeof accuracy if the actuators are feedback controlled based on thecontrol target value and the posture information of the arm members sothat the arm members may assume the predetermined postures, the finishaccuracy in a desired construction operation can be further augmented.

Furthermore, the arm member posture detection means may be constructedas extension/contraction displacement detection means for detectingextension/contraction displacement information of the cylinder typeactuators. In this instance, since posture information can be obtainedsimply and conveniently with a very simple construction, thiscontributes very much to simplification of the present controlapparatus.

Meanwhile, the control means may be constructed as means for controllingthe cylinder type actuators by feedback controlling systems which atleast have a proportion operation factor and an integration operationfactor so that the arm members may individually assume predeterminedpostures, and have second correction means for regulating, when the loadto the actuators detected by the actuator load detection means is higherthan the predetermined value, feedback control by the integrationoperation factor in response to the load conditions of the cylinder typeactuators.

Where such a construction as just described is employed, when the loadto the actuators described above is higher than the predetermined value,if the feedback control of the actuators by the integration operationfactor is regulated in response to the load condition, then theextension/contraction displacement velocities can be prevented fromcontinuing to be increased by the integration operation factor withcertainty while necessary minimum extension/contraction displacementvelocities of the actuators are secured (maintained) by the proportionaloperation factor. Accordingly, a desired construction operation can beperformed with a higher degree of accuracy and efficiently.

The first correction means may be constructed so as to increase areduction amount of the control target value to reduce theextension/contraction displacement velocity by the cylinder typeactuators as the load to the actuators increases. In this instance,since the extension/contract displacement velocities of the actuatorscan be reduced (varied) very smoothly by simple and easy setting, thiscontributes very much to simplification and augmentation in performanceof the present control apparatus.

Furthermore, the second correction means may be constructed so as toincrease the regulation amount of the feedback control by theintegration operation factor as the load to the cylinder type actuatorsincreases. By this, since an increase of the extension/contractiondisplacement velocities of the actuators by the integration operationfactor can be regulated very rapidly by simple and easy setting, alsothis contributes very much to simplification and augmentation inperformance of the present control apparatus.

Further, the control means may include third correction means forincreasing, under a transition condition wherein the load to thecylinder type actuators detected by the actuator load detection meanschanges from a condition wherein the load is higher than thepredetermined value to another condition wherein the load is lower thanthe predetermined value, the extension/contraction displacementvelocities by the cylinder type actuators based on a result obtainedthrough integration means which moderates a variation of a detectionresult obtained by the actuator load detection means.

With such a construction as just described, since, even if the load tothe actuators is removed suddenly, the extension/contractiondisplacement velocities of them can be caused to increase moderately,the arm members can be controlled very smoothly to augment the finishaccuracy in a desired construction operation very much.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a boom connected at one end thereof forpivotal motion to the construction machine body, a stick connected atone end thereof for pivotal motion to the boom by a joint part andhaving a bucket, which is capable of excavating the ground at a tipthereof and accommodating sand and earth therein, mounted for pivotalmotion at the other end thereof, a boom hydraulic cylinder interposedbetween the construction machine body and the boom for pivoting the boomwith respect to the construction machine body by expanding orcontracting a distance between end portions thereof, a stick hydrauliccylinder interposed between the boom and the stick for pivoting thestick with respect to the boom by expanding or contracting a distancebetween end portions thereof, control target value setting means fordetermining a control target value from operation position informationof operation members, control means for controlling the boom hydrauliccylinder and the stick hydraulic cylinder based on the control targetvalue obtained by the control target value setting so that the bucketmay move at a predetermined moving velocity, and hydraulic cylinder loaddetection means for detecting a load condition of the boom hydrauliccylinder or the stick hydraulic cylinder, and the control means includesfourth correction means for reducing, when any of the cylinder loadsdetected by the hydraulic cylinder load detection means is higher than apredetermined value, the control target value set by the target valuesetting means in response to the cylinder load condition to reduce thebucket moving velocity by the boom hydraulic cylinder and the stickhydraulic cylinder.

With such a constructed as just described, when the load to thehydraulic cylinders is higher than the predetermined value, since thehydraulic cylinders are controlled to reduce the control target value toreduce the extension/contraction displacement velocities of them, evenif the load to the hydraulic cylinders is removed (reduced) suddenly,the extension/contraction displacements of them can be controlled verysmoothly without allowing them to vary suddenly. Consequently, thefinish accuracy in a desired construction operation can be augmentedremarkably.

The control apparatus for a construction machine may be constructed suchthat it comprises boom posture detection means for detecting postureinformation of the boom, and stick posture detection means for detectingposture information of the stick, and the control means is constructedso as to feedback control the boom hydraulic cylinder and the stickhydraulic cylinder based on the control target value obtained by thecontrol target value setting means and the posture information of theboom and the stick detected by the boom posture detection means and thestick posture detection means so that the bucket may move at apredetermined moving velocity.

In this instance, if the hydraulic cylinders are feedback controlledbased on the control target value and the posture information of theboom and the stick so that the bucket may move at the predeterminedvelocity, then since the boom and the stick can be controlled so as toassume predetermined postures with a higher degree of accuracy, thefinish accuracy in a desired construction operation can be furtheraugmented.

The stick posture detection means may be constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the stick hydrauliccylinder, and the boom posture detection means may be constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the boom hydrauliccylinder. This contributes very much to simplification of the presentapparatus since posture information can be obtained simply andconveniently with a very simple construction.

The control means may be constructed as means for controlling the boomhydraulic cylinder and the stick hydraulic cylinder based on the controltarget value by feedback controlling systems which have at least aproportion operation factor and an integration operation factor so thatthe bucket may move at the predetermined moving velocity, and includefifth correction means for regulating, when the cylinder load detectedby the hydraulic cylinder load detection means is higher than apredetermined value, the feedback control by the integration operationfactor in response to the cylinder load condition.

In this instance, the extension/contraction displacement velocities canbe prevented from continuing to be increased by the integrationoperation factor with certainty while necessary minimumextension/contraction displacement velocities of the hydraulic cylindersare secured (maintained) by the proportion operation factor.Accordingly, a desired construction operation can be performed with ahigher degree of accuracy and efficiently.

Further, where the fourth correction means is constructed so as toincrease the reduction amount of the control target value to reduce thebucket moving velocity as the cylinder load increases, since the bucketmoving velocity can be reduced (varied) very smoothly by simple and easysetting, this contributes very much to simplification and augmentationin performance of the present control apparatus.

Further, where the fifth correction means is constructed so as toincrease the regulation amount of the feedback control by theintegration operation factor as the cylinder load increases, since anincrease of the bucket moving velocity by the integration operationfactor can be regulated very rapidly by simple and easy setting, alsothis contributes very much to simplification and augmentation inperformance of the present control apparatus.

Furthermore, the control means may include sixth correction means forincreasing, under a transition condition wherein any of the cylinderloads detected by the hydraulic cylinder load detection means changesfrom a condition wherein the load is higher than the predetermined valueto another condition wherein the load is lower than the predeterminedvalue, the bucket moving velocity by the boom hydraulic cylinder and thestick hydraulic cylinder based on a result obtained through integrationmeans which moderates a variation of a detection result obtained by thehydraulic cylinder load detection means.

Where such a construction as described above is employed, even when theload to the hydraulic cylinders is removed suddenly, the bucket movingvelocity can be caused to increase moderately, and accordingly, the armmembers can be controlled very smoothly to increase the finish accuracyin a desired construction operation remarkably.

It is to be noted that, if the integration means is a low-pass filter,then the controls described above can be realized readily with a verysimple construction.

Further, the present control apparatus is effectively particularly wherefluid pressure circuits (hydraulic circuits) for the actuators(hydraulic cylinders) described above are open center type circuits withwhich extension/contraction displacement velocities of the actuators(hydraulic cylinders) depend upon a load acting upon the actuators(hydraulic cylinders), and can always control very smoothly withoutallowing the extension/contraction displacements of the actuators(hydraulic cylinders) to vary suddenly.

Further, according to the present invention, a control apparatus for aconstruction machine wherein, when a working member mounted for pivotalmotion at an end of a joint type arm mechanism provided on aconstruction machine body is actuated by cylinder type actuators, thecylinder type actuators are controlled based on a control target valuedetermined from operation position information of operation members byfeedback controlling systems which have a proportion operation factor,an integration proportion factor and a differentiation operation factorso that the working member may assume a predetermined posture, ischaracterized in that feedback control by the proportion operationfactor, the differentiation operation factor and the integrationoperation factor is performed when a first condition that the operationpositions of the operation members are inoperative positions and controldeviations of the feedback controlling systems are higher than apredetermined value is satisfied, but when the first condition is notsatisfied, feedback control by the integration operation factor isinhibited and feedback control by the proportion operation factor andthe differential operation factor is performed.

Further, according to the present invention, a control apparatus for aconstruction machine is characterized in that it comprises aconstruction machine body, a working member mounted on the constructionmachine body by a joint type arm mechanism, a cylinder type actuatormechanism having cylinder type actuators for actuating the workingmember by performing extension/contraction operations, control targetvalue setting means for determining a control target value fromoperation position information of operation members, posture detectionmeans for detecting posture information of the working member, controlmeans for controlling the cylinder type actuators based on the controltarget value obtained by the control target value setting means and theposture information of the working member detected by the posturedetection means by feedback controlling systems which have aproportional operation factor, an integration operation factor and adifferentiation operation factor so that the working member may assume apredetermined posture, operation position detection means for detectingwhether or not operation positions of the operation members are ininoperative positions, and control deviation detection means fordetecting whether or not control deviations of the feedback controllingsystems are higher than a predetermined value, and the control meansincludes first control means for performing feedback control by theproportion operation factor, the differentiation operation factor andthe integration operation factor when a first condition that theoperation positions of the operation members detected by the operationposition detection means are the inoperative positions and the controldeviations of the feedback controlling systems detected by the controldeviation detection means are higher than the predetermined value issatisfied, and second control means for inhibiting feedback control bythe integration operation factor and performing feedback control by theproportion operation factor and the differentiation operation factorwhen the first condition is not satisfied.

It is to be noted that the posture detection means may be constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of the cylinder typeactuators.

Further, the joint type arm mechanism may be composed of a boom and astick connected for pivotal motion relative to each other by a jointpart, and the working member may be constructed as a bucket which ismounted for pivotal motion on the stick and is capable of excavating theground at a tip thereof and accommodating sand and earth therein.

With such a construction as described above, while the operation membersare in the operative positions, since feedback control by theintegration operation factor is inhibited, a large variation of thecontrol target value of the cylinder type actuators which arises from bythe integration operation factor can be regulated. Accordingly, when theoperation members are in the inoperative positions and the controldeviation is higher than the predetermined value, if feedback control bythe integration operation factor is added to feedback control by theproportion operation factor and the differentiation operation factor,then a control deviation which cannot be reduced fully to zero whereonly feedback control by the proportion operation factor and thedifferentiation operation factor is performed can be reduced close tozero very rapidly, and consequently, the working member can becontrolled to a desired posture rapidly and accurately and the workingmember can be controlled with a very high degree of accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a hydraulic excavator on which acontrol apparatus according to a first embodiment of the presentinvention is provided;

FIG. 2 is a view schematically showing a construction of a controlsystem according to the first embodiment of the present invention;

FIG. 3 is a view schematically showing a construction of an entirecontrolling system of the control apparatus according to the firstembodiment of the present invention;

FIG. 4 is a view showing a constriction of the entire control systemaccording to the first embodiment of the present invention;

FIG. 5 is a block chart of the control apparatus according to the firstembodiment of the present invention;

FIG. 6 is a schematic block diagram showing essential part of thecontrol apparatus according to the first embodiment of the presentinvention;

FIG. 7 is a view illustrating a control characteristic of the controlapparatus according to the first embodiment of the present invention;

FIG. 8 is a schematic view of operating parts of the hydraulic excavatorto which the first embodiment of the present invention is applied;

FIG. 9 is a schematic view illustrating an operation of the hydraulicexcavator to which the first embodiment of the present invention isapplied;

FIG. 10 is a schematic view illustrating an operation of the hydraulicexcavator to which the first embodiment of the present invention isapplied;

FIG. 11 is a schematic view illustrating an operation of the hydraulicexcavator to which the first embodiment of the present invention isapplied;

FIG. 12 is a schematic view illustrating an operation of the hydraulicexcavator to which the first embodiment of the present invention isapplied;

FIG. 13 is a schematic view illustrating an operation of the hydraulicexcavator to which the first embodiment of the present invention isapplied;

FIG. 14 is a view showing a general construction of a conventionalpopular hydraulic excavator;

FIG. 15 is a control block diagram of essential part according to asecond embodiment of the present invention;

FIG. 16 is a view for explaining a characteristic of correction of acontrol gain of the control apparatus according to the second embodimentof the present invention;

FIG. 17 is a view for explaining a characteristic of correction of acontrol gain of the control apparatus according to the second embodimentof the present invention;

FIG. 18 is a view for explaining a characteristic of correction of acontrol gain of the control apparatus according to the second embodimentof the present invention;

FIG. 19 is a view for explaining a characteristic of correction of acontrol gain of the control apparatus according to the second embodimentof the present invention;

FIG. 20 is a control block diagram of essential part according to athird embodiment of the present invention;

FIG. 21 is a control block diagram wherein attention is paid tofunctions of essential part according to the third embodiment of thepresent invention;

FIG. 22(a) is a view for explaining an operation according to the thirdembodiment of the present invention and is a view illustrating anexample of a deviation between a target cylinder position and an actualcylinder position;

FIG. 22(b) is a view for explaining an operation according to the thirdembodiment of the present invention and is a view illustrating anexample of correction of a target value;

FIG. 23 is a view showing a construction of an entire control systemaccording to a fourth embodiment of the present invention;

FIG. 24 is a control block diagram of essential part according to thefourth embodiment of the present invention;

FIG. 25 is a control block diagram of essential part according to thefourth embodiment of the present invention;

FIG. 26 is a view for explaining a characteristic of a weightcoefficient addition section according to the fourth embodiment of thepresent invention;

FIG. 27 is a control block diagram of essential part according to afifth embodiment of the present invention;

FIG. 28 is a view illustrating an example of setting of a weightcoefficient according to the fifth embodiment of the present invention;

FIG. 29 is a block diagram schematically showing a construction of anentire control apparatus according to a sixth embodiment of the presentinvention;

FIG. 30 is a block diagram showing a functional construction of acorrection circuit of the control apparatus according to the sixthembodiment of the present invention;

FIG. 31 is a control block diagram of essential part according to aseventh embodiment of the present invention;

FIG. 32 is a view for explaining a characteristic of a target cylindervelocity correction section according to the seventh embodiment of thepresent invention;

FIG. 33 is a view for explaining a characteristic of an I gaincorrection section according to the seventh embodiment of the presentinvention;

FIG. 34 is a control block diagram of essential part according to aneighth embodiment of the present invention;

FIG. 35 is a control block diagram of essential part according to theeighth embodiment of the present invention; and

FIG. 36 is a schematic view of operating parts of a hydraulic excavatorto which the eighth embodiment of the present invention is applied.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, embodiments of the present invention are describedwith reference to the drawings.

(1) Description of the First Embodiment

First, a control apparatus for a construction machine according to afirst embodiment of the present invention is described. The controlapparatus for a construction machine of the present embodiment isconstructed such that, even if an operation lever or the like isoperated suddenly upon starting of operation or ending of operation in asemiautomatic control mode, a variation of an instruction value to ahydraulic cylinder is smooth.

Here, a hydraulic excavator as a construction machine according to thepresent embodiment includes, as shown in FIG. 1, an upper revolving unit(construction machine body) 100 with an operator cab 600 for revolvingmovement in a horizontal plane on a lower traveling unit 500 which hascaterpillar members 500A on the left and right thereof.

A boom (arm member) 200 having one end connected for swingable motion isprovided on the upper revolving unit 100, and a stick (arm member) 300connected at one end thereof for swingable motion by a joint part isprovided on the boom 200.

A bucket (working member) 400 which is connected at one end thereof forswingable motion by a joint part and can excavate the ground with a tipthereof and accommodate earth and sand therein is provided on the stick300.

In this manner, in the present embodiment, a joint type arm mechanism iscomposed of the boom 200, stick 300 and bucket 400. In particular, ajoint type arm mechanism which is mounted at one end portion thereof forswingable motion on the upper revolving unit 100 and has the bucket 400on the other end side thereof and further has at least a pair of arms(boom 200 and stick 300) connected to each other by the joint part iscomposed.

Further, a boom hydraulic cylinder 120, a stick hydraulic cylinder 121and a bucket hydraulic cylinder 122 (in the following description, theboom hydraulic cylinder 120 may be referred to as boom cylinder 120 ormerely as cylinder 120, the stick hydraulic cylinder 121 may be referredto as stick cylinder 121 or merely as cylinder 121, and the buckethydraulic cylinder 122 may be referred to as bucket cylinder 122 ormerely as cylinder 122) as cylinder type actuators are provided.

Here, the boom hydraulic cylinder 120 is connected at one end thereoffor swingable motion to the upper revolving unit 100 and is connected atthe other end thereof for swingable motion to the boom 200. In otherwords, the boom cylinder 120 is interposed between the upper revolvingunit 100 and the boom 200, such that, as the distance between theopposite end portions is expanded or contracted, the boom 200 can bepivoted with respect to the upper revolving unit 100.

The stick cylinder 121 is connected at one end thereof for swingablemotion to the boom 200 and connected at the other end thereof forswingable motion to the stick 300. In other words, the stick cylinder121 is interposed between the boom 200 and the stick 300, such that, asthe distance between the opposite end portions is expanded orcontracted, the stick 300 can be pivoted with respect to the boom 200.

The bucket cylinder 122 is connected at one end thereof for swingablemotion to the stick 300 and connected at the other end thereof forswingable motion to the bucket 400. In other words, the bucket cylinder122 is interposed between the stick 300 and the bucket 400, such that,as the distance between the opposite end portions thereof is expanded orcontracted, the bucket 400 can be pivoted with respect to the stick 300.It is to be noted that a linkage 130 is provided at a free end portionof the bucket hydraulic cylinder 122.

In this manner, a cylinder type actuator mechanism having a plurality ofcylinder type actuators for driving the arm mechanism by performingexpanding and contracting operations is composed of the cylinders 120 to122 described above.

It is to be noted that, though not shown in the figure, also hydraulicmotors for driving the left and right caterpillar members 500A and arevolving motor for driving the upper revolving unit 100 to revolve areprovided.

By the way, as shown in FIG. 2, a hydraulic circuit (fluid pressurecircuit) for the cylinders 120 to 122, the hydraulic motors and therevolving motor described above is provided, and pumps 51 and 52 whichare driven by an engine 700, main control values (main control valves)13, 14 and 15 and so forth are interposed in the hydraulic circuit.

Further, in order to control the main control valves 13, 14 and 15, apilot hydraulic circuit is provided, and a pilot pump 50, solenoidproportional valves 3A, 3B and 3C, solenoid directional control valves4A, 4B and 4C, selector valves 18A, 18B and 18C and so forth driven bythe engine 700 are interposed in the pilot hydraulic circuit. It is tobe noted that, in FIG. 2, where each line which interconnects differentcomponents is a solid line, this represents that this line is anelectric system, but where each line which interconnects differentcomponents is a broken line, this represents that the line is ahydraulic system.

By the way, a controller (controlling means) 1 for controlling the maincontrol valves 13, 14 and 15 via the solenoid proportional valves 3A, 3Band 3C to control the boom 200, the stick 300 and the bucket 400 so thatthey may have desired extension/contraction displacements is provided.It is to be noted that the controller 1 is composed of a microprocessor,memories such as a ROM and a RAM, suitable input/output interfaces andso forth.

To the controller 1, detection signals (including setting signals) fromvarious sensors are inputted, and the controller 1 executes the controldescribed above based on the detection signals from the sensors. It isto be noted that such control by the controller 1 is calledsemiautomatic control, and even in a semiautomatic excavation mode, itis possible to manually effect fine adjustment of the bucket angle andthe target slope face height during excavation.

As a mode of the semiautomatic control described above, a bucket anglecontrol mode (refer to FIG. 9), a slope face excavation mode (bucket tiplinear excavation mode or raking mode) (refer to FIG. 10), a smoothingmode which is a combination of the slope face excavation mode and thebucket angle control mode (refer to FIG. 11), a bucket angle automaticreturn mode (automatic return mode) (refer to FIG. 12) and so forth areavailable.

Here, the bucket angle control mode is a mode in which the angle (bucketangle) of the bucket 400 with respect to the horizontal direction(vertical direction) is always kept constant even if the stick 300 andthe boom 200 are moved as shown in FIG. 9, and this mode is executed ifa bucket angle control switch on a display switch panel shown in FIG. 2or a monitor panel 10 with a target slope face setting unit (which ishereinafter referred to merely as monitor panel) is switched ON. It isto be noted that this mode is cancelled when the bucket 400 is movedmanually, and a bucket angle at a point of time when the bucket 400 isstopped is stored as a new bucket holding angle.

The slope face excavation mode is a mode in which a tip 112 of thebucket 400 moves linearly as shown in FIG. 10. However, in thisinstance, the bucket hydraulic cylinder 122 does not move, andaccordingly, the bucket angle φ (angle of the tip 112 of the bucket 400with respect to a slop face) varies as the bucket 400 moves.

The slope face excavation mode + bucket angle control mode (smoothingmode) is a mode in which the tip 112 of the bucket 400 moves linearlyand also the bucket angle φ is kept constant during excavation as shownin FIG. 11.

The bucket automatic return mode is a mode in which the bucket angle isautomatically returned to an angle set in advance as shown in FIG. 12,and the return bucket angle is set by the monitor panel 10. This mode isstarted when a packet automatic return start switch 7 on an operationlever 6 is switched ON, and this mode is cancelled at a point of timewhen the bucket 400 returns to the angle set in advance. It is to benoted that the operation lever 6 is an operation member for operatingboth of the boom 200 and the bucket 400, and is hereinafter referred toas boom operation lever or boom/bucket operation lever.

Further, the slope face excavation mode and the smoothing mode describedabove are started when a semiautomatic control switch on the monitorpanel 10 is switched ON and a slope face excavation switch 9 on a stickoperation lever 8 is switched ON and besides both or either one of thestick operation lever 8 and the boom/bucket operation lever 6 is moved.It is to be noted that the target slope face angle is set by a switchoperation on the monitor panel 10.

Further, in the slope face excavation mode and the smoothing mode, abucket tip moving velocity in a parallel direction to the target slopeface angle is set by the operation amount of the stick operation lever8, and a bucket tip moving velocity in the perpendicular direction tothe target slope face angle is set by the operation amount of theboom/bucket operation lever 6.

Accordingly, if the stick operation lever 8 is operated, then the buckettip 112 starts its linear movement along the target slope face angle,and fine adjustment of the target slope face angle by a manual operationcan be performed by moving the boom/bucket operation lever 6 duringexcavation.

Further, if the stick operation lever 8 and the boom/bucket operationlever 6 are operated at the same time, then the moving direction and themoving velocity of the bucket tip 112 are determined by a compositevector of the parallel and vertical directions with respect to the setinclined face (slope face).

Further, in the slope face excavation mode and the smoothing mode, notonly the bucket angle during excavation can be adjusted finely byoperating the boom/bucket operation lever 6, but also the target slopeface height can be changed. In other words, also in the semiautomaticexcavation modes, fine adjustment of the bucket angle and the targetslope face height can be performed manually during excavation.

It is to be noted that, in the present system, also a manual mode ispossible, and in this manual mode, not only operation equivalent to thatof a conventional hydraulic excavator is possible, but also coordinateindication of the tip 112 of the bucket 400 is possible.

Also a service mode for performing service maintenance of the entiresemiautomatic system is prepared, and this service mode is enabled byconnecting an external terminal 2 to the controller 1. And, by thisservice mode, adjustment of control gains, initialization of varioussensors and so forth are performed.

By the way, as the various sensors connected to the controller 1, asshown in FIG. 2, pressure switches 16, pressure sensors 19, 28A and 28B,resolvers (angle sensors) 20 to 22, an inclination angle sensor 24 andso forth are provided. Further, to the controller 1, an engine pumpcontroller 27, ON-OFF switches 7 and 9, the monitor panel 10 areconnected. It is to be noted that the external terminal 2 is connectedto the controller 1 upon adjustment of the control gains, initializationof the sensors and so forth.

It is to be noted that the engine pump controller 27 receives enginespeed information from an engine rotational speed sensor 23 and controlsthe engine 700, and the engine pump controller 27 can communicatecoordination information with the controller 1. Further, detectionsignals of the resolvers 20 to 22 are inputted to the controller 1 via asignal converter (conversion means) 26.

The pressure sensors 19 are sensors which are attached to pilot pipesconnected from the operation lever 8 for the stick 300 and the operationlever 6 for the boom 200 to the main control valves 13, 14 and 15 anddetect pilot hydraulic pressures in the pilot pipes. Since the pilothydraulic pressures in such pilot lines are varied by the operationamounts of the operation levers 6 and 8, the operation amounts of theoperation levers 6 and 8 can be estimated by measuring the hydraulicpressures.

The pressure sensors 28A and 28B detect hydraulic pressures supplied tothe boom cylinder 120 and the stick cylinder 121 to detectextension/contraction conditions of the cylinders 120 and 121.

The pressure switches 16 are attached to the pilot pipes for theoperation levers 6 and 8 with selectors 17 or the like interposedtherebetween and are provided as neutral detection switches fordetecting whether or not the operation positions of the operation levers6 and 8 are neutral. Then, when the operation lever 6 or 8 is in theneutral condition, the output of the pressure switch 16 is OFF, but whenthe operation lever 6 or 8 is operated (when it is not in a neutralcondition), the output of the pressure switch 16 is ON. It is to benoted that the pressure switches 16 are used also for detection of anabnormal condition of the pressure sensors 19 and for switching betweenthe manual/semiautomatic modes.

The resolver 20 is provided at a pivotally mounted portion (joint part)of the boom 200 on the upper revolving unit 100 and functions as a firstangle sensor for detecting (monitoring) the posture of the boom 200. Theresolver 21 is provided at a pivotally mounted portion (joint part) ofthe stick 300 on the boom 200 and functions as a second angle sensor fordetecting (monitoring) the posture of the stick 300. Further, theresolver 22 is provided at a linkage pivotally mounted portion andfunctions as a third angle sensor for detecting (monitoring) the postureof the bucket 400. By those resolvers 20 to 22, angle detection meansfor detecting the posture of the arm mechanism in angle information iscomposed.

The signal converter (conversion means) 26 converts angle informationobtained by the resolver 20 into extension/contraction displacementinformation of the boom cylinder 120, converts angle informationobtained by the resolver 21 into extension/contraction of the stickcylinder 121, and converts angle information obtained by the resolver 22into extension/contraction of the bucket cylinder 122, that is, convertsangle information obtained by the resolvers 20 to 22 into correspondingextension/contraction displacement information of the cylinders 120 to122. To this end, the signal converter 26 includes an input interface26A for receiving signals from the resolvers 20 to 22, a memory 26Bincluding a lookup table 26B-1 for storing extension/contractiondisplacement information of the cylinders 120 to 122 corresponding toangle information obtained by the resolvers 20 to 22, a main arithmeticunit (CPU) 26C which can calculate the extension/contractiondisplacement information of the cylinders 120 to 122 corresponding toangle information obtained by the resolvers 20 to 22 and communicate thecylinder extension/contraction displacement information with thecontroller 1, an output interface 26D for sending out the cylinderextension/contraction displacement information from the main arithmeticunit (CPU) 26C, and so forth.

By the way, the extension/contraction displacement information θbm, θstand θbk of the cylinders 120 to 122 corresponding to the angleinformation λbm, λst and λbk obtained by the resolvers 20 to 22 can becalculated using the cosine theorem in accordance with the followingexpressions:

    λbm=[L.sub.101102.sup.2 +L.sub.101111.sup.2 -2L.sub.101102 ·L.sub.101111 cos(θbm+Axbm)].sup.1/2       (1-1)

    λst=[L.sub.103104.sup.2 +L.sub.104105.sup.2 -2L.sub.103104 ·L.sub.104105 cos θst].sup.1/2             (1-2)

    λbk=[L.sub.106107.sup.2 +L.sub.107109.sup.2 -2L.sub.106107 ·L.sub.107109 cos θbk].sup.1/2             (1-3)

Here, in the expressions above, L_(ij) represents a fixed length, Axbmrepresents a fixed angle, and the suffix ij to L has information betweenthe nodes i and j. For example, L₁₀₁₁₀₂ represents the distance betweenthe node 101 and the node 102. It is to be noted that the position ofthe node 101 is determined as the origin of the xy coordinate system(refer to FIG. 8).

Naturally, each time the angle information θbm, θst and θbk is obtainedby the resolvers 20 to 22, the expressions above may be calculated byarithmetic means (for example, the CPU 26C). In this instance, the CPU26C forms the arithmetic means which calculates, from the angleinformation obtained by the resolvers 20 to 22, extension/contractiondisplacement information of the cylinders 120 to 122 corresponding tothe angle information by calculation.

It is to be noted that signals obtained by the conversion by the signalconverter 26 are utilized not only for feedback control uponsemiautomatic control but also to measure coordinates formeasurement/indication of the position of the bucket tip 112.

The position of the bucket tip 112 in a semiautomatic control mode iscalculated using a certain one point of the upper revolving unit 100 ofthe hydraulic excavator as the origin. However, when the upper revolvingunit 100 is inclined in the front linkage direction, it is necessary tocorrect the coordinate system for control calculation by an angle bywhich the vehicle is inclined. The inclination sensor 24 is provided inorder to correct the coordinate system.

The solenoid proportional valves 3A to 3C receive control signals fromthe controller 1 and control the hydraulic pressures supplied from thepilot pump 50, and the controlled hydraulic pressures are passed throughthe control valves 4A to 4C or the selector valves 18A to 18C so as toact upon the main control valves 13, 14 and 15 to control the spoolpositions of the main control valves 13, 14 and 15 so that targetcylinder velocities may be obtained.

On the other hand, if the control valves 4A to 4C are changed over tothe manual mode side, then the cylinders 120 to 122 can be controlledmanually.

It is to be noted that a stick confluence control proportional valve 11adjusts the confluence ratio of the two pumps 51 and 52 in order toobtain an oil amount corresponding to a target cylinder velocity.

Further, the ON-OFF switch (slope face excavation switch) 9 is mountedon the stick operation lever 8, and as an operator operates this switch,selection or no selection of a semiautomatic control mode is performed.Then, if a semiautomatic control mode is selected, then the bucket tip112 can be moved linearly as described above.

Furthermore, the ON-OFF switch (packet automatic return start switch) 7is mounted on the boom/bucket operation lever 6, and as an operatorswitches the switch 7 ON, the bucket 400 can be automatically returnedto an angle set in advance.

Safety valves 5 are provided to switch the pilot pressures to besupplied to the solenoid proportional valves 3A to 3C, and only when thesafety valves 5 are in an ON state, the pilot pressures are supplied tothe solenoid proportional valves 3A to 3C. Accordingly, when somefailure occurs in semiautomatic control or in a like case, automaticcontrol can be stopped rapidly by switching the safety valves 5 to anOFF state.

By the way, the rotational speed of the engine 700 is differentdepending upon the position of the engine throttle set by an operator,and further, even if the engine throttle is fixed, the engine rotationalspeed varies depending upon the load. Since the pumps 50, 51 and 52 aredirectly coupled to the engine 700, if the engine rotational speedvaries, then also the pump discharges vary, and consequently, even ifthe spool positions of the main control valves 13, 14 and 15 are fixed,the cylinder velocities are varied by the variation of the enginerotational speed. Thus, in order to correct this, the engine rotationalspeed sensor 23 is attached to the engine 700. In particular, when theengine rotational speed is low, the target moving velocity of the buckettip 112 is set slow.

The monitor panel 10 is not only used as a setting unit for the targetslope face angle α (refer to FIGS. 8 and 13) and the packet returnangle, but also used as an indicator for coordinates of the bucket tip112, the slope face angle α measured or the distance between coordinatesof two points measured. It is to be noted that the monitor panel 10 isprovided in the operator cab 600 together with the operation levers 6and 8.

In particular, in the system according to the present embodiment, thepressure sensors 19 and the pressure switches 16 are incorporated inconventional pilot hydraulic lines to detect operation amounts of theoperation levers 6 and 8 and feedback control is effected using theresolvers 20, 21 and 22, and such control makes it possible to effectmultiple freedom degree feedback control independently for each of thecylinders 120, 121 and 122. Consequently, the requirement for additionof an oil unit such as a pressure compensation valve is eliminated. Itis to be noted that an influence of inclination of the upper revolvingunit 100 is corrected using the vehicle inclination angle sensor 24.Further, an operator can select a mode (semiautomatic modes and manualmode) arbitrarily using the change-over switch 9 and besides can set atarget slope face angle α.

In the following, a control algorithm of the semiautomatic control mode(except the bucket automatic return mode) effected by the controller 1is described with reference to FIG. 4.

In particular, the moving velocity and direction of the bucket tip 122are first calculated based on information of the target slope face setangle, the pilot hydraulic pressures for controlling the stick cylinder121 and the boom cylinder 120, the vehicle inclination angle and theengine rotational speed. Then, target velocities of the cylinders 120,121 and 122 are calculated based on the information. In this instance,the information of the engine rotational speed is used to determine anupper limit to the cylinder velocities.

Further, the controller 1 includes, as shown in FIGS. 3 and 4, controlsections 1A, 1B and 1C provided independently of each other for thecylinders 120, 121 and 122, and the controls are constructed asindependent control feedback loops as shown in FIG. 4 so that they maynot interfere with each other.

Further, the compensation construction in the closed loop controls(refer to FIG. 4) has, in each of the control sections 1A, 1B and 1C, amultiple freedom degree construction including a feedback loop and afeedforward loop with regard to the displacement and the velocity asshown in FIG. 5.

In particular, if a target velocity is given, then as regards feedbackloop processing, processes according to a route wherein a deviationbetween the target velocity and feedback information of the cylindervelocity (time differentiation of the cylinder position) is multipliedby a predetermined gain Kvp (refer to reference numeral 62), anotherroute wherein the target velocity is integrated once (refer to anintegration element 61 of FIG. 5) and a deviation between the targetvelocity integration information and displacement feedback informationis multiplied by a predetermined gain Kpp (refer to reference numeral63) and a further route wherein the deviation between the targetvelocity integration information and the displacement feedbackinformation is multiplied by a predetermined gain Kpi (refer toreference numeral 64) and further integrated (refer to reference numeral66) are performed while, as regards the feedforward loop processing, aprocess by a route wherein the target velocity is multiplied by apredetermined gain Kf (refer to reference numeral 65) is performed.

It is to be noted that the values of the gains Kvp, Kpp, Kpi and Kf canbe changed by a gain scheduler 70.

Further, while a non-linearity removal table 71 is provided to removenon-linear properties of the solenoid proportional valves 3A to 3C, themain control valves 13 to 15 and so forth, a process in which thenon-linearity removal table 71 is used is performed at a high speed by acomputer using a table lookup technique.

By the way, while the control section 1A for the boom cylinder 120, thecontrol section 1B for the stick cylinder 121 and the control section 1Cfor the bucket cylinder 122 are provided independently of each other inthe controller 1 as shown in FIGS. 3 and 4, each of the control section1A for the boom cylinder 120 and the control section 1B for the stickcylinder 121 includes such target moving velocity setting means 100a asshown in FIG. 6. It is to be noted that, while FIG. 6 is a block diagramwherein attention is paid to the control section 1B, also the controlsection 1A of the boom cylinder 120 has a construction similar to thatof FIG. 6.

Here, the target moving velocity setting means 100a as essential part ofthe present invention is described. The target moving velocity settingmeans 100a is provided in order to prevent instruction values to thecontrol valves 3A and 3B for the hydraulic cylinders 120 and 121 fromvarying instantly even if an operator operates the operation lever 6 or8 suddenly upon starting of an operation or upon ending of an operationby a semiautomatic control mode.

In particular, where such target moving velocity setting means 100a asdescribed above is not provided, if an operator operates the operationlever 6 or 8 suddenly upon starting of an operation or the like of asemiautomatic control mode, then control signals to the solenoid valves3A to 3C suddenly vary instantly. In this instance, the operations ofthe main control valves (main control valves) 13, 14 and 15 fail tofollow up the pilot pressures sent out from the solenoid valves 3A to3C, and the operations of the hydraulic cylinders 120 to 122 accompanyvibrations, an impact or the like and cannot be started or endedsmoothly.

This is because, in a semiautomatic control mode, the operationvelocities of the stick 300 and the boom 200 are determined in responseto the operation amounts of the operation levers 6 and 8, and in orderto eliminate such a situation as described above, it is a possible ideato set the moving velocity of the bucket tip 112 so as to graduallyincrease (ramp up) even if the operation lever 6 or 8 is operatedsuddenly or to provide a smooth velocity variation through a low-passfilter.

However, since the control signals to the main control valves 13 to 15of the cylinders 120 to 122 are fed-back information (cylinder velocityinformation) obtained by time differentiation of the cylinder positionsas described with reference to FIG. 5, even if the ramp up processdescribed above or the like is performed, when the operation lever 6 or8 is operated suddenly, the control signal (instruction value) to theboom cylinder 120 or the stick cylinder 121 still varies instantly andthe operations of the boom 200, stick 300 and bucket 400 cannot bestarted smoothly.

Therefore, in the present invention, the target moving velocity settingmeans 100a is provided in each of the control sections 1A and 1B in thecontroller 1 so that, even if the operation lever 6 or 8 is operatedsuddenly upon starting of an operation or upon ending of an operation insuch a semiautomatic control mode as described above, the hydrauliccylinders 120 to 122 and the boom 200 and/or the stick 300 may operatesmoothly.

Here, the target moving velocity setting means 100a includes, as shownin FIG. 6, a target moving velocity outputting section 102, a storagesection (memory) 103 and a comparison section 104.

The target moving velocity outputting section 102 outputs target movingvelocity data (first target moving velocity data) of the hydrauliccylinders 120 to 122 in accordance with the positions of the operationlevers 6 and 8. In particular, in the target moving velocity outputtingsection 102, a relationship between the operation position of theoperation lever 6 or 8 and the target moving velocity of the hydrauliccylinder 120 or 121 is set linearly so that the operation position ofthe operation lever 6 or 8 may be reflected directly as a target movingvelocity of the hydraulic cylinder 120 or 121.

The storage section 103 stores target moving velocity data (secondtarget moving velocity data) with which time differentiation of thetarget moving velocity characteristic by the operation lever 6 or 8results in a characteristic of a similar type upon starting of anoperation or upon ending of an operation in a semiautomatic controlmode.

Here, as seen in FIG. 7, in the present embodiment, such target movingvelocity data with which the moving velocity of the bucket tip 112exhibits a cosine wave characteristic (cos curve) upon starting of anoperation or upon ending of an operation in a semiautomatic control modeare stored in the storage section 103.

The reason why the target moving velocity characteristic is set so thattime differentiation thereof results in a characteristic of a similartype upon starting of an operation or upon ending of an operation in asemiautomatic control mode is that the control valves 13 and 14 whichdrive the cylinders 120 and 121 feed back cylinder velocity information(that is, differentiation information of the cylinder positions) as seenin FIGS. 4 and 5.

In particular, due to such setting, also velocity information fed backfrom a target moving velocity can be provided with a characteristic (sincurve) similar to the characteristic (for example, a cos curve) of thetarget moving velocity information, and control signals produced takingthe feedback information into consideration do not vary discontinuously(instantly) and can operate the solenoid valves 3A to 3C continuouslyand consequently can operate the hydraulic cylinders 120 to 122smoothly.

Accordingly, even if an operator operates the operation lever 6 or 8suddenly, for example, upon starting of an operation in a semiautomaticcontrol mode, the instruction values (control signals) to the controlvalves 13 and 14 can be provided with continuous characteristics.

It is to be noted that the target moving velocity data (second targetmoving velocity data) stored in the storage section 103 are not limitedto such a cosine wave characteristic as shown in FIG. 7, but any data(for example, a sin curve or a natural logarithm curve) may be used if acharacteristic of a similar type is obtained by differentiation of thedata. However, where a response in operation or the like is taken intoconsideration, preferably the target moving velocity data are set to acosine wave characteristic.

The comparison section 104 compares data outputted from the storagesection 103 described above and data outputted from the target movingvelocity outputting section 102 with each other and outputs a lower oneof the data as target moving velocity information.

It is to be noted that such comparison section 104 and target movingvelocity outputting section 102 as described above are provided by thefollowing reason.

In particular, the present apparatus is provided to allow the boom 200,stick 300 and bucket 400 and the hydraulic cylinders 120 to 122 tooperate smoothly when the operation lever 6 or 8 is operated suddenlyupon starting of an operation or the like in a semiautomatic mode, andfrom such a point of view as just described, only the storage section103 should be provided, but such target moving velocity outputtingsection 102 and comparison section 104 as described above need notnecessarily be provided. However, for example, where a skilled operatoroperates, the operator may possibly operate the operation lever 6 or 8in a condition more appropriate than by such control of the hydrauliccylinders by the storage section 103.

In such a case, the operability is better if the operation of theoperator takes precedence to operate the hydraulic cylinders 120 to 122.Further, in this instance, there is little necessity to effect controlof the hydraulic cylinders 120 to 122 using data outputted from thestorage section 103.

Therefore, such a comparator 104 as described above is provided so that,of data obtained by the target moving velocity outputting section 102(that is, an operation condition of the operation lever 6 or 8) and dataoutputted from the storage section 103, lower data, that is, that datawhich exhibits a smaller variation in target moving velocity, isoutputted as target moving velocity information.

Since the control apparatus for a construction machine according to thefirst embodiment of the present invention is constructed in such amanner as described above, when such a slope face excavating operationof a target slope face angle α as shown in FIG. 13 is performed bysemiautomatic control using the hydraulic excavator, such semiautomaticcontrol functions as described above can be realized.

In particular, when detection signals (including setting information ofa target slope face angle α) from the various sensors are inputted tothe controller 1 mounted on the hydraulic excavator, the controller 1sets control signals for the solenoid proportional valves 3A, 3B and 3Cbased on the detection signals from the sensors (including detectionsignals of the resolvers 20 to 22 received via the signal converter 26)and operation conditions of the operation levers 6 and 8.

Then, the main control valves 13, 14 and 15 operate in response to pilothydraulic pressures from the solenoid proportional valves 3A, 3B and 3Cto control the boom 200, stick 300 and bucket 400 so that they mayexhibit desired extension/contraction displacements thereby to effectsuch semiautomatic control as described above.

Meanwhile, upon the semiautomatic control, the moving velocity anddirection of the bucket tip 112 are first calculated from information ofthe target slope face set angle, the pilot hydraulic pressures which areset based on the operation conditions of the operation levers 6 and 8and control the stick cylinder 121 and the boom cylinder 120, thevehicle inclination angle, the engine rotational speed and so forth, andtarget velocities of the cylinders 120, 121 and 122 are calculated basedon the information. In this instance, the information of the enginerotational speed is required when an upper limit to the cylindervelocities is determined. Further, since such controls are constructedas the feedback loops independent of each other for the cylinders 120,121 and 122, they do not interfere with each other.

Particularly, in the present apparatus, since such target movingvelocity setting means 100a as seen in FIG. 5 are provided in thecontroller 1, even if an operator operates the operation lever 6 or 8suddenly upon starting of an operation or upon ending of an operation ina semiautomatic control mode, the boom 200, stick 300 and bucket 400operate smoothly.

In particular, while information obtained by time differentiation of thepositions of the hydraulic cylinders 120 to 122 is fed back into thecontroller 1 as seen in FIGS. 4 and 5, since, in the present invention,the characteristic of the target moving velocity is set by the storagesection 103 so that the differentiation information to be fed back andthe target moving velocity characteristic upon starting of an operationor upon ending of an operation set by the operation levers 6 and 8 mayhave characteristics of a similar type as seen in FIGS. 6 and 7, controlsignals outputted to the solenoid valves 3A to 3C become continuouscontrol signals, and the control signals are suppressed from varyinginstantly suddenly.

Accordingly, such a situation that, upon starting of an operation orupon ending of an operation by semiautomatic control, the operations ofthe main control valves 13, 14 and 15 fail to follow up pilot pressuressent out from the solenoid valves 3A to 3C can be eliminated, and theboom 200, stick 300 and bucket 400 can operate smoothly.

Further, in the present apparatus, since the target moving velocityoutputting section 102 which outputs target moving velocity data (firsttarget moving velocity data) of the hydraulic cylinders 120 to 122 inaccordance with the positions of the operation levers 6 and 8 and thecomparison section 104 which compares data outputted from the storagesection 103 and the data (second target moving velocity data) outputtedfrom the target moving velocity outputting section 102 with each otherand outputs a lower one of the data as target moving velocityinformation are provided, for example, if a skilled operator operatesthe operation lever 6 or 8 in a condition more appropriate than bycontrol of the hydraulic cylinders by the storage section 103, theoperation by the operator takes precedence to control the operations ofthe hydraulic cylinders 120 to 122, and consequently, the operability isnot deteriorated.

It is to be noted that the setting of the target slope face angle α inthe semiautomatic system can be performed by a method which is based oninputting of a numerical value by switches on the monitor panel 10, atwo point coordinate inputting method, or an inputting method by abucket angle, and similarly, for the setting of the bucket return anglein the semiautomatic system, a method which is based on inputting of anumerical value by the switches on the monitor panel 10 or a methodwhich is based on bucket movement is performed. For all of them, knowntechniques are used.

Further, the semiautomatic control modes described above and thecontrolling methods therein are performed in the following manner basedon cylinder extension/contraction displacement information obtained byconversion by the signal converter 26 of the angle information detectedby the resolvers 20 to 22.

First, in the bucket angle control mode (refer to FIG. 9), the length ofthe bucket cylinder 122 is controlled so that the angle (bucket angle) φdefined between the bucket 400 and the x axis may be fixed at eacharbitrary position. In this instance, the bucket cylinder length λbk canbe calculated using the boom cylinder length λbm, the stick cylinderlength λst and the angle φ mentioned above as parameters.

In the smoothing mode (refer to FIG. 11), since the bucket angle φ iskept fixed, the bucket tip position 112 and a node 108 move in parallel.First, a case wherein the node 108 moves in parallel to the x axis(horizontal excavation) is described below.

In particular, in this instance, the coordinates of the node 108 in thelinkage posture when excavation is started are represented by (x₁₀₈,y₁₀₈) , and the cylinder lengths of the boom cylinder 120 and the stickcylinder 121 in the linkage posture in this instance are calculated andthe velocities of the boom 200 and the stick 300 are calculated so thatx₁₀₈ may move horizontally. It is to be noted that the moving velocityof the node 108 depends upon the operation amount of the stick operationlever 8.

On the other hand, where parallel movement of the node 108 isconsidered, the coordinates of the node 108 after the very short time Δtare represented by (x₁₀₈ +Δx, y₁₀₈). Δx is a very small displacementwhich depends upon the moving velocity. Accordingly, by taking Δx intoconsideration of x₁₀₈, target lengths of the boom and stick cylindersafter Δt can be calculated.

In the slope face excavation mode (refer to FIG. 10), control isperformed in a similar manner as in the smoothing mode. However, thepoint which moves is changed from the node 108 to the bucket tipposition 112, and further, the control takes it into consideration thatthe bucket cylinder length λbk is fixed.

Further, in correction of a finish inclination angle by the vehicleinclination angle sensor 24, calculation of the front linkage positionis performed on the xy coordinate system whose origin is a node 101 ofFIG. 8. Accordingly, if the vehicle body is inclined with respect to thexy plane, then the xy coordinates are inclined with respect to theground surface (horizontal plane), and the target inclination angle withrespect to the ground surface is varied. In order to correct this, theinclination angle sensor 24 is mounted on the vehicle, and when it isdetected by the inclination angle sensor 24 that the vehicle body isinclined by β with respect to the xy plane, the target inclination angleis corrected by replacing it with a value obtained by adding β to it.

Prevention of deterioration of the control accuracy by the enginerotational speed sensor 23 is such as follows. In particular, withregard to correction of the target bucket tip velocity, the targetbucket tip velocity depends upon the operation positions of the stickand boom operation levers 6 and 8 and the engine rotational speed.Meanwhile, since the hydraulic pumps 51 and 52 are directly coupled tothe engine 700, when the engine rotational speed is low, also the pumpdischarges are small and the cylinder velocities are low. Therefore, theengine rotational speed is detected, and the target bucket tip velocityis calculated so as to conform with the variation of the pumpdischarges.

Meanwhile, with regard to correction of the maximum values of the targetcylinder velocities, correction is performed taking it intoconsideration that the target cylinder velocities are varied by theposture of the linkage and the target slope face inclination angle andthat, when the pump discharges decrease as the engine rotationalvelocity decreases, also the maximum cylinder velocities must bedecreased. It is to be noted that, if a target cylinder velocity exceedsits maximum cylinder velocity, then the target bucket tip velocity isdecreased so that the target cylinder velocity may not exceed themaximum cylinder velocity.

While the various control modes and the controlling methods in thecontrol modes are described above, they all employ a technique whereinthey are performed based on cylinder extension/contraction displacementinformation, and control contents according to this technique arepublicly known. In particular, in the system according to the presentembodiment, since angle information is detected first by the resolvers20 to 22 and then the angle information is converted into cylinderextension/contraction displacement information by the signal converter26, the known controlling technique can be used for later processing.

While various controls are performed by the controller 1 in this manner,in the system according to the present invention, since angleinformation signals detected by the resolvers 20 to 22 are convertedinto cylinder displacement information by the signal converter 26 andthen inputted to the controller 1, control in which cylinderextension/contraction displacements which are used in a conventionalcontrol system are used can be executed even if an expensive strokesensor for detecting an extension/contraction displacement of each ofthe cylinders for the boom 200, stick 300 and bucket 400 as in the priorart is not used. Consequently, while the cost is suppressed low, asystem which can control the position and the posture of the bucket 400accurately and stably can be provided.

Further, since the feedback control loops are independent of each otherfor the cylinders 120, 121 and 122 and the control algorithm is multiplefreedom control of the displacement, velocity and feedforward, thecontrol system can be simplified. Further, since the non-linearity of ahydraulic apparatus can be converted into linearity at a high speed by atable lookup technique, the present system contributes also toaugmentation of the control accuracy.

Furthermore, since deterioration of the control accuracy by the positionof the engine throttle and the load variation is corrected by correctingthe influence of the vehicle inclination by the vehicle inclinationsensor 24 or reading in the engine rotational speed, the present systemcontributes to realization of more accurate control.

Further, since also maintenance such as gain adjustment can be performedusing the external terminal 2, also an advantage that adjustment or thelike is easy can be obtained.

Furthermore, since operation amounts of the operation levers 7 and 8 arecalculated based on variations of the pilot pressures using the pressuresensors 19 and so forth and besides a conventional open center valvehydraulic system is utilized as it is, there is an advantage thataddition of a pressure compensation valve or the like is not required,and also it is possible to display the bucket tip coordinates on thereal time basis on the monitor panel 10 with a target slope face anglesetting unit. Further, due to the construction which employs the safetyvalve 5, also an abnormal operation when the system is abnormal can beprevented.

Meanwhile, the target moving velocity data (second target movingvelocity data, refer to FIG. 6) stored in the storage section 103 of thecontroller 1 are not limited to such a cosine wave characteristic asshown in FIG. 7, but any data (for example, a sin curve or a naturallogarithm curve) may be used if a characteristic of a similar type isobtained by differentiation of the data. However, where a response inoperation or the like is taken into consideration, preferably the targetmoving velocity data are set to a cosine wave characteristic.

Further, while, in the present first embodiment, a target movingvelocity characteristic upon starting of an operation and a targetmoving velocity characteristic upon ending of an operation are set tothe same characteristic (that is, a cosine wave characteristic), thetarget moving velocity characteristics upon starting of an operation andupon ending of an operation may be different from each other if acharacteristic of a similar type is obtained by differentiation.

(2) Description of the Second Embodiment

In the following, a control apparatus for a construction machineaccording to a second embodiment is described principally with referenceto FIGS. 15 to 19. It is to be noted that the general construction of aconstruction machine to which the present second embodiment is appliedis similar to the contents described hereinabove with reference to FIG.1 and so forth in connection with the first embodiment described above,and the general construction of controlling systems of the constructionmachine is similar to the contents described hereinabove with referenceto FIGS. 2 to 4 in connection with the first embodiment described above.Further, the forms of representative semiautomatic modes of theconstruction machine are similar to the contents described hereinabovewith reference to FIGS. 9 to 14 in connection with the first embodimentdescribed above. Therefore, description of portions corresponding tothem is omitted, and in the following, description principally ofdifferences from the first embodiment is given.

Now, the present second embodiment is constructed such that stabilizedcontrol can be performed against load variations to the hydrauliccylinders or a temperature variation of the operating oil.

In particular, it is supposed that, in an operation (such as ahorizontal leveling operation) of moving the bucket tip positionlinearly by the slope face excavation mode in semiconductor control, theloads to the hydraulic cylinders 120 to 122 during an excavationoperation are varied by the shape of the ground, the excavation amountor the like. In such a case, where conventional PID control is employed,there is the possibility that the degrees of positioning accuracy of thehydraulic cylinders 120 to 122 or the degree of accuracy of the locus ofthe bucket tip position may be deteriorated.

Further, where feedback control is performed for the hydraulic cylinders120 to 122, also it is supposed that variations of the dynamiccharacteristics of control objects (for example, the hydraulic cylinders120 to 122 or the solenoid valves provided in the hydraulic circuits)arising from a temperature variation of the operating oil have aninfluence on the control performances of the closed loops, resulting indeterioration of the stability of the controlling systems.

In order to eliminate such a situation as described above, the controlgains of the closed loops should be reduced to increase the gain marginsor the phase margins. However, it is supposed that this may result indeterioration of the degrees of positioning accuracy of the hydrauliccylinders 120 to 122 or of the degree of accuracy of the locus of thebucket tip position.

The control apparatus for a construction machine according to the secondembodiment of the present invention is constructed so as to solve suchsubjects as described above and allows stable control against loadvariations to the hydraulic cylinders or a temperature variation of theoperating oil.

First, a control algorithm of the semiautomatic control mode (except thebucket automatic return mode) which is performed by the controller 1 inthe present second embodiment is described with reference to FIG. 15.Target value setting means 80 is provided in the controller 1, andtarget velocities (target operation information) of the boom 200, thebucket 400 and so forth are set in accordance with the positions ofoperation levers 6 and 8.

In particular, the moving velocity and direction of the bucket tip 112are first calculated from information of a target slope face set angle,pilot hydraulic pressures which control the stick cylinder 121 and theboom cylinder 120, a vehicle inclination angle and an engine rotationalspeed. Then, target velocities of the cylinders 120, 121 and 122 arecalculated based on the information. In this instance, the informationof the engine rotational speed is used as a parameter for determining anupper limit to the cylinder velocities.

Meanwhile, the controller 1 includes control sections 1A, 1B and 1Cindependent of each other for the cylinders 120, 121 and 122, and theindividual controls are formed as independent control feedback loops anddo not interfere with each other (refer to FIGS. 3 and 4).

Here, essential part of the control apparatus for a constriction machineof the present embodiment is described. The compensation construction inthe closed loop controls (refer to FIG. 4) has, in each of the controlsections 1A, 1B and 1C, a multiple freedom degree construction includinga feedback loop and a feedforward loop with regard to the displacementand the velocity as shown in FIG. 15, and includes feedback loop typecompensation means 72 having a variable control gain (controlparameter), and feedforward type compensation means 73 having a variablecontrol gain (control parameter).

In particular, if a target velocity is given, then feedback loopprocesses according to a route wherein a deviation between the targetvelocity and velocity feedback information is multiplied by apredetermined gain Kvp (refer to reference numeral 62), another routewherein the target velocity is integrated once (refer to an integrationelement 61 of FIG. 15) and a deviation between the target velocityintegration information and displacement feedback information ismultiplied by a predetermined gain Kpp (refer to reference numeral 63)and a further route wherein the deviation between the target velocityintegration information and the displacement feedback information ismultiplied by an I gain coefficient (refer to reference symbol 64a) anda predetermined gain Kpi (refer to reference numeral 64) and furtherintegrated (refer to reference numeral 66) are performed by the feedbackloop type compensation means 72 while, by the feedforward typecompensation means 73, a feedforward loop process by a route wherein thetarget velocity is multiplied by a predetermined gain Kf (refer toreference numeral 65) is performed.

Of the processes mentioned, the feedback loop processes are described inmore detail. The present apparatus includes, as shown in FIG. 15,operation information detection means 91 for detecting operationinformation of the cylinders 120 to 122, and the controller 1 receivesthe detection information from the operation information detection means91 and target operation information (for example, target movingvelocities) set by the target value setting means 80 as inputinformation and sets control signals so that the arms such as the boom200 and the working member (bucket) 400 may exhibit target operationconditions.

Further, the operation information detection means 91 particularly iscylinder position detection means 83 which can detect positions of thehydraulic cylinders 120 to 122, and in the present embodiment, thecylinder position detection means 83 is composed of the resolversresolvers 20 to 22 and the signal converter 26 described hereinabove.The cylinder position detection means 83 also has a function asoperation condition detection means 90 which will be hereinafterdescribed, and detection means 93 is composed of such operationinformation detection means 91 as described above and the operationcondition detection means 90 which will be hereinafter described.

Meanwhile, the values of the gains Kvp, Kpp, Kpi and Kf mentioned abovecan individually be varied by the gain scheduler (control parameterscheduler) 70, and the boom 200, the bucket 400 and so forth can becontrolled to target operation conditions by varying or correcting thevalues of the gains Kvp, Kpp, Kpi and Kf in this manner.

In particular, the present apparatus includes, as shown in FIG. 15,operation condition detection means 90 which in turn includes oiltemperature detection means 81 for detecting the oil temperature of theoperating oil, cylinder load detection means 82 for detecting the loadsto the cylinders 120 to 122, and cylinder position detection means 83for detecting position information of the cylinders. The gain scheduler70 varies the gains Kvp, Kpp, Kpi and Kf based on the detectioninformation from the operation condition detection means 90 (that is,operation information of the construction machine).

The oil temperature detection means 81 is a temperature sensor providedin the proximity of the solenoid proportional valve 3A, 3B or 3C, andthe gain scheduler 70 corrects the gains in response to the temperaturerelating to the cylinders 120 to 122.

Here, the temperature relating to the hydraulic cylinders 120 to 122 is,for example, the temperature of controlling oil (pilot oil), and here,the temperature of the pilot oil is detected as a representative oiltemperature which represents the temperature of the operating oil.

Meanwhile, a map having such a characteristic as illustrated in FIG. 16is stored in the gain scheduler 70, and the gains Kvp, Kpp, Kpi and Kfare corrected using representative oil temperature information detectedby the oil temperature detection means 81.

Here, a characteristic of the gain correction illustrated in FIG. 16 isdescribed briefly. The gain correction characteristic is basically setto such a characteristic that the gains are lowered as the oiltemperature of the pilot oil rises. This is because it is intended toprevent the control performances of the closed loops from beingdeteriorated by variations of the dynamic characteristics of controlobjects such as the hydraulic cylinders 120 to 122, the solenoid valves3A to 3C or the like caused by temperature variations of the operatingoil and it is intended to keep the stability of the controlling systems.

It is to be noted that such a representative oil temperature asdescribed above is not limited to the temperature of the pilot oildescribed above, but the temperature of the main operating oil used forcontrol (operating oil supplied to or discharged from oil chambers ofthe cylinders 120 to 122) may be used as a representative oiltemperature. In this instance, preferably a temperature sensor isprovided in an operating oil tank.

Further, the gains Kvp, Kpp, Kpi and Kf may be corrected using both ofthe temperature of the pilot oil and the temperature of the mainoperating oil for control (in the following description, such mainoperating oil temperature is referred to as tank oil temperature). Inthis instance, a representative oil temperature is calculated, forexample, in accordance with the following expression:

    Representative oil temperature=tank oil temperature×W+pilot oil temperature×(1-W)

In the expression above, W is a coefficient to be used for weightingrepresenting which one of the tank oil temperature and a pilot oiltemperature should be taken into consideration preferentially as arepresentative oil temperature, and is set within a range of 0≦W≦1. As Wapproaches 1, the representative oil temperature takes the tank oiltemperature into consideration with a higher degree of preference, butas W approaches 0, the representative oil temperature takes the pilotoil temperature into consideration with a higher degree of preference.

Further, the weight coefficient W is set to such a characteristic asillustrated in FIG. 17, and is set such that, as the instruction values(solenoid valve driving currents) for the solenoid valves 3A to 3Cdecreases, W approaches 0, but as the instruction value increases, Wapproaches 1.

This is because, when the instruction values to the solenoid valves 3Ato 3C are small, that is, when it is intended to cause the solenoidvalves 3A to 3C and the cylinders 120 to 122 to operate comparativelyslowly, a variation of the pilot oil temperature has a significantinfluence on the dynamic characteristics of the controlling systems.Also there is another reason that, when the openings of the solenoidvalves 3A to 3C are very small, the influence of the pilot oiltemperature is significant.

It is to be noted that, where the gains Kvp, Kpp, Kpi and Kf arecorrected using both of the pilot oil temperature and the tank oiltemperature as described above, such a map as shown in FIG. 17 isprovided in the oil temperature detection means 81, and only informationof a representative oil temperature calculated in the oil temperaturedetection means 81 is inputted to the gain scheduler 70.

Subsequently, the cylinder load detection means 82 which composes theoperation condition detection means 90 is described. The cylinder loaddetection means 82 detects loads to the cylinders 120 and 121, and thegain scheduler 70 fetches the load information of the cylinders 120 and121 and corrects the proportional gains Kpp and Kf.

It is to be noted that the cylinder load detection means 82 is composedparticularly of the pressure sensors 28A and 28B shown in FIG. 2 and soforth, and detects loads to the cylinders 120 to 122 based oninformation from the pressure sensors 28A and 28B and so forth.

Meanwhile, a map having such a characteristic as illustrated in FIG. 18is stored in the gain scheduler 70, and the gain scheduler 70 correctsthe gains Kpp and Kf using load information of the cylinders 120 to 122detected by the cylinder load detection means 82 and the map illustratedin FIG. 18.

It is to be noted that, since generation of noise or the like issupposed if correction of the gains Kvp and Kpi is performed, in thepresent embodiment, correction of the gains Kvp and Kpi based on thecylinder loads is not performed.

Here, a characteristic of the map illustrated in FIG. 18 is describedbriefly. In this correction map for the proportional gains Kpp and Kf,the proportional gains Kpp and Kf are gradually increased as thecylinder load increases. In other words, where the loads acting upon thehydraulic cylinders 120 and 121 are high in this manner, the gains areincreased because damping increases.

Then, control deviations can be reduced by correcting (scheduling) thecontrol gains Kpp and Kf of the PID feedback type compensation means 72and the feedforward type compensation means 73 in response the cylinderloads to the boom 200, stick 300 and bucket 400 in this manner, andaccurate control of the boom 200, stick 300 and bucket 400 can berealized.

Subsequently, the cylinder position detection means 83 which composesthe operation condition detection means 90 is described. The cylinderposition detection means 83 detects actual cylinder positions of theboom cylinder 120 and the stick cylinder 121 and is composed of theresolvers 20 to 22 and the signal converter 26.

Here, in the present embodiment, the cylinder positions are detected byfetching angle information detected by the resolvers 20 to 22 into thesignal converter 26 and converting the angle information into cylinderdisplacement information in the signal converter 26.

Then, the gain scheduler 70 fetches also the position information of thehydraulic cylinders 120 and 121 and corrects the proportional gains Kppand Kf of the boom 200 and the stick 300.

It is to be noted that, while such correction of the proportional gainsKpp and Kf based on the cylinder positions is performed principally forthe boom cylinder 120 and the stick cylinder 121, this is because theloads applied upon working in such semiautomatic control modes asdescribed above almost act upon the boom cylinder 120 and the stickcylinder 121.

Further, the gain scheduler 70 includes a map (refer to FIG. 19) forvarying the gains Kpp and Kf based on detection information from thecylinder position detection means 83.

As shown in FIG. 19, in the map, characteristics independent of eachother are set individually for the gains Kpp and Kf of the boom 200 andthe stick 300, and the gains for the boom 200 and the stick 300 areindividually corrected in different manners upon stick-in and stick-out.

Here, the stick-in signifies a movement when the stick 300 is moved tothe nearer side, and the stick-out signifies a movement when the stick300 is moved to the farther side.

The axis of abscissa of the map shown in FIG. 19 is the displacement ofthe stick cylinder 121, and when the displacement of the stick cylinder121 is small, this is when the tip 112 of the bucket 400 is positionedfar away, but when the displacement of the stick cylinder 121 is large,the tip 112 of the bucket 400 is positioned on the nearer side.

First, the correction characteristics of the proportional gains Kpp andKf of the boom 200 upon stick-out are described. The correctioncharacteristics are each set such that, upon stick-out, when thedisplacement of the stick cylinder 121 comes to an intermediateposition, the correction value of the gain exhibits a minimum value, andwhen the stick cylinder 121 is expanded or the contracted from theintermediate position, the gain correction value increases while drawinga curve like a substantially quadratic curve as indicated by a curve 1.

Meanwhile, the proportional gains Kpp and Kf of the stick 300 are set tosuch characteristics that, as indicated by another curve 2, when thedisplacement of the stick cylinder 121 is smaller than a predetermineddisplacement, they are set to a substantially fixed value, but when thedisplacement becomes larger than the predetermined displacement, theyincrease gradually.

Further, the proportional gains Kpp and Kf of the boom 200 upon stick-inare set, as indicated by a curve 3, to a characteristic similar to thecharacteristic upon stick-out (the curve 1), that is, to such acharacteristic that, when the displacement of the stick cylinder 121comes to a substantially intermediate position, the gain correctionvalue exhibits a minimum value, but when the displacement of the stickcylinder 121 is expanded or contracted from the intermediate position,the gain correction value increases while drawing a curve like asubstantially quadratic curve.

This is because, when the displacement of the stick cylinder 121 issmall, since the stick 300 is expanded and the tip 112 of the bucket 400is positioned far away, the load applied to the stick cylinder 121 orthe stick cylinder 122 is high, and consequently, the gains must be madehigh. However, if the gain correction amount is made excessively large,then it is supposed that the entire controlling system becomes unstable,and taking it into consideration that the control accuracy (accuracy ofthe tip position) is deteriorated, correction by such a large amountthat it exceeds that in correction upon stick-out of the boom 200indicated by the curve 1 is not performed.

On the other hand, when the displacement of the stick cylinder 121 comesclose to the intermediate position, the stability of the controlaccuracy is secured by decreasing the gains.

Further, when the displacement of the stick cylinder 121 is large, sincethe tip 112 of the bucket 400 is positioned on the nearer side and bothof the boom 200 and the stick 300 take comparatively upright postures,the components of force in the parallel direction are likely to becomeshort with respect to the directions in which the hydraulic cylinders120 and 121 operate. Therefore, when the displacement of the stickcylinder 121 is large, such correction as to increase the gains isperformed. It is to be noted that, also in this instance, similarly asin the case wherein the cylinder displacement is small described above,since it is considered that, if the gain correction amount is setexcessively large, then the entire controlling system becomes unstable,correction by an amount larger than a predetermined amount is notperformed taking deterioration of the control accuracy (accuracy of thetip position) into consideration.

In contrast, the correction characteristics of the proportional gainsKpp and Kf of the stick 300 upon stick-in are set such that, asindicated by a curve 4, when the displacement of the stick cylinder 121is small, the gains are set to high values, but when the stick cylinder121 is expanded exceeding the predetermined displacement, the gainsbecome substantially fixed. This is because the operation upon stick-inis an operation wherein the tip 112 of the bucket 400 moves to thenearer side and, upon movement in such a direction, since the bucket tip112 side becomes an advancing direction, when the position of the tip112 of the bucket 400 is in the neighborhood on the nearer side, thestick cylinder 121 can perform an operation with a comparatively smallforce.

By the way, while the controller 1 of the present apparatus includes theoperation condition detection means 90 which is composed of the oiltemperature detection means 81, cylinder load detection means 82 andcylinder position detection means 83 as described above and the gainscheduler 70 corrects control gains based on information detected by thedetection means 81 to 83, if detection information from the detectionmeans 81 to 83 is inputted simultaneously to the gain scheduler 70 and aplurality of correction values are set for one gain (for example, forthe proportional gain Kpp) based on the detection information, then thegain scheduler 70 outputs a sum total of the correction values as afinal correction gain.

In this instance, taking the stability of the controlling systems intoconsideration, upper limit values and lower limit values to the gaincorrection amounts are set in the gain scheduler 70, and if a correctionamount exceeding an upper limit value or another correction valuesmaller than a lower limit value is set, then correction is performedusing the upper limit value or the lower limit value as a limit.

The control apparatus for a construction machine according to the secondembodiment of the present invention is advantageous in that, since thecontroller 1 includes a gain controller capable of varying controlparameters (control gains) in response to an operation condition of theconstruction machine detected by the operation condition detection means90 and is constructed in such a manner as to vary and correct the gainsbased on maps having such characteristics as illustrated in FIGS. 16 to19, there is an advantage that the control gains are corrected inresponse to an operation condition of the construction machine uponworking and working can be performed always by a stabilized operation.

Further, while it is supposed that, conventionally, when feedbackcontrol is performed for the cylinders 120 to 122, variations of thedynamic characteristics of control objects (for example, the cylinders120 to 122 and the solenoid valves 3A to 3C) by a temperature variationof operating oil have an influence on the controlling performances ofthe closed loops and the stability of the controlling systems isdeteriorated, with the control apparatus for a construction machine ofthe present second embodiment, deterioration of the degrees ofpositioning accuracy of the cylinders 120 to 122 and the degree ofaccuracy of the locus of the bucket tip position can be prevented.

Further, since an oil temperature variation of the operating oil iscompensated for by the oil temperature detection means 81 and loadvariations to the cylinders 120 to 122 are compensated for by thecylinder load detection means 82 and besides the position deviations ofthe hydraulic cylinders 120 to 122 are compensated for by the cylinderposition detection means 83, accurate tip position control can beexecuted.

It is to be noted that, while the present embodiment is constructed suchthat correction of the control gains by the gain scheduler 70 isperformed by correction based on the oil temperature variations of theoperating oil, correction based on the loads to the cylinders 120 to 122and correction based on the positions and the directions of operationsof the hydraulic cylinders 120 to 122, the control apparatus for aconstruction machine of the present embodiment is not limited to such aform as just described, but, for example, only one of the threecorrections (for example, the correction based on the oil temperaturevariations of the operating oil) may be performed, or any two of thethree corrections may be performed in combination.

(3) Description of the Third Embodiment

Now, a control apparatus for a construction machine according to a thirdembodiment is described principally with reference to FIGS. 20 to 22(a)and 22(b). It is to be noted that the general construction of aconstruction machine to which the present third embodiment is applied issimilar to the contents described above with reference to FIG. 1 and soforth in connection with the first embodiment described above, and thegeneral construction of a controlling system of the construction machineis similar to the contents described above with reference to FIGS. 2 to4 in connection with the first embodiment described above. Further, theforms of the representative semiautomatic modes of the constructionmachine are similar to the contents described above with reference toFIGS. 9 to 14 in connection with the first embodiment described above.Therefore, description of portions corresponding to them is omitted, andin the following, description principally of differences from the firstembodiment is given.

Now, the present third embodiment is constructed such that, when thearms 120 to 122 of the construction machine are automaticallycontrolled, a deviation between target operation information and actualoperation information is eliminated to the utmost to achieveaugmentation of the control accuracy.

In particular, when locus control (tracking control) of the boom 200,stick 300 and bucket 400 is performed by feedback control in asemiautomatic control mode, since instruction values to the cylinders120 to 122 are calculated based on deviations of the feedback (that is,control errors between input information and output information), it isdifficult to reduce the deviations during operation of the cylinders tozero, and as a result, the bucket tip position sometimes exhibits anerror from a target value.

In particular, in such feedback control, since actual cylinder positionsand cylinder velocities are detected and compared with target cylinderpositions and target cylinder velocities and control is performed sothat the deviations may approach zero, it is difficult to eliminate thedeviations completely during control, resulting in production of acontrol error.

The control apparatus for a construction machine according to the thirdembodiment of the present invention is constructed so as to solve such aproblem as described above and eliminates, when the boom 200, the stick300 and the bucket 400 are automatically controlled, deviations betweentarget operation information and actual operation information to theutmost.

First, a control algorithm of the semiautomatic control modes (exceptthe packet automatic return mode) performed by the controller 1 in thepresent third embodiment is described. Target value setting means 80 isprovided in the controller 1 so that target velocities (target operationinformation) of the boom 200, the bucket 400 and so forth are set inresponse to the positions of the operation levers 6 and 8.

In particular, the moving velocity and direction of the bucket tip 112are first calculated from information of a target slope face set angle,pilot hydraulic pressures which control the stick cylinder 121 and theboom cylinder 120, a vehicle inclination angle and an engine rotationalspeed. Then, based on the information, target velocities of thecylinders 120, 121 and 122 are calculated. In this instance, theinformation of the engine rotational speed is used as a parameter fordetermining an upper limit to the cylinder velocities.

Meanwhile, the controller 1 includes control sections 1A, 1B and 1Cindependent of each other for the boom cylinder cylinders 120, 121 and122, and the individual controls are formed as independent controlfeedback loops and do not interfere with each other (refer to FIGS. 3and 4).

The compensation construction in the closed loop controls (refer to FIG.4) has, in each of the control sections 1A, 1B and 1C, a multiplefreedom degree construction of a feedback loop and a feedforward loopwith regard to the displacement and the velocity as shown in FIG. 20,and includes feedback loop type compensation means 72 having a variablecontrol gain (control parameter), and feedforward type compensationmeans 73 having a variable control gain (control parameter).

In particular, if a target velocity is given, then feedback loopprocesses according to a route wherein a deviation between the targetvelocity and velocity feedback information is multiplied by apredetermined gain Kvp (refer to reference numeral 62), another routewherein the target velocity is integrated once (refer to an integrationelement 61 of FIG. 20) and a deviation between the target velocityintegration information and displacement feedback information ismultiplied by a predetermined gain Kpp (refer to reference numeral 63)and a further route wherein the deviation between the target velocityintegration information and the displacement feedback information ismultiplied by an I gain coefficient (refer to reference symbol 64a) anda predetermined gain Kpi (refer to reference numeral 64) and furtherintegrated (refer to reference numeral 66) are performed by the feedbackloop type compensation means 72 while, by the feedforward typecompensation means 73, a feedforward loop process by a route wherein thetarget velocity is multiplied by a predetermined gain Kf (refer toreference numeral 65) is performed.

Here, in the present apparatus, cylinder position detection means 83 isprovided as operation information detection means 91 for detectingoperation information of the cylinders 120 to 122, and the controller 1receives the detection information from the operation informationdetection means 91 and target operation information (for example, targetmoving velocities) set by the target value setting means 80 as inputinformation and sets control signals so that the arms such as the boom200 and the working member (bucket) 400 may exhibit target operationconditions.

Further, in the present embodiment, the cylinder position detectionmeans 83 is composed of the resolvers 20 to 22 and the signal converter26 described hereinabove. The cylinder position detection means 83detects the cylinder positions by fetching angle information detected bythe resolvers 20 to 22 into the signal converter 26 and converting theangle information into cylinder displacement information in the signalconverter 26. Further, by time differentiating the detection informationfrom the cylinder position detection means 83, not only positioninformation of the cylinders but also cylinder velocity information isfed back.

It is to be noted that the values of the gains Kvp, Kpp, Kpi and Kfmentioned above can individually be varied by the gain scheduler 70, andthe gain scheduler 70 corrects the values of the gains Kvp, Kpp, Kpi andKf based on temperature information of the operating oil, loadinformation of the cylinders 120 to 122 and so forth in a similar manneras in the second embodiment.

Further, while a non-linearity removal table 71 is provided to removenon-linear properties of the solenoid proportional valves 3A to 3C, themain control valves 13 to 15 and so forth, a process in which thenon-linearity removal table 71 is used is performed at a high speed by acomputer using a table lookup technique.

In the following, essential part of the control apparatus for aconstruction machine of the third embodiment is described.

In the present embodiment, actual cylinder position information andcylinder velocity information are fed back as input information by thefeedback loop type compensation means 72, and the controller 1 controlsoperations of the cylinders 120 to 122 based on the information so thatthe boom 200, the bucket 400 and so forth may exhibit target operationconditions.

However, in such feedback control, since actual cylinder positions andcylinder velocities are detected and compared with target cylinderpositions and target cylinder velocities and control is performed sothat the deviations between them may approach zero, it is difficult toeliminate the deviations completely during control.

Thus, in the present invention, correction information storage means 140for storing correction information for correcting target operationinformation set by the target value setting means 80 is provided asshown in FIGS. 20 and 21, and the hydraulic cylinders 120 to 122 arecontrolled based on correction target operation information from thecorrection information storage means 140 so that the boom 200 and thebucket 400 may exhibit target operation conditions.

In particular, upon working by a semiautomatic control mode, asimulation operation is performed a predetermined number of times (oronce) prior to starting of the working in accordance with controlsignals set by the target value setting means 80, and deviations(correction information) between target position information of thehydraulic cylinders 120 to 122 and actual cylinder position informationobtained from the operation information detection means 91 (particularlythe cylinder position detection means 83) are stored into the correctioninformation storage means 140.

Then, upon starting of the working, error information corresponding tothe deviations stored in the correction information storage means 140 isadded to the control signals set by the target value setting means 80 sothat signals in which the deviations are included in advance areoutputted to the hydraulic cylinders 120 to 122.

Then, by performing such control as described above, accurate bucketposition control can be executed in a semiautomatic control mode.

Now, the correction information storage means 140 is described in alittle more detail here. The correction information storage means 140 iscomposed of, as shown in FIG. 21, target position correction informationstorage means 141 for storing correction information for correctingtarget position information of the cylinders set by the target valuesetting means 80, and target velocity correction information storagemeans 142 for storing correction information for correcting targetvelocity information of the cylinders set by the target value settingmeans 80. Further, as shown in FIG. 21, the correction informationstorage means 140 is provided for each of the controlling systems forthe boom cylinder 120, the stick cylinder 121 and the stick cylinder122.

It is to be noted that the target position correction informationstorage means 141 and the target velocity correction information storagemeans 142 which compose the correction information storage means 140 areconstructed in a similar manner to each other, and the followingdescription is given using the target position correction informationstorage means 141 representing the storage means 141 and 142.

The target position correction information storage means 141 includes,as shown in FIG. 21, a storage section (memory) 141a, an amplifier 141b,an input switch (Sin) 141c and an output switch (Sout) 141d, and if theinput switch 141c is closed, then a deviation (correction information)between cylinder target position information set by the target valuesetting means 80 and an actual cylinder position detected by thecylinder position detection means 83 is inputted to the storage section141a so that the deviation is stored into the storage section 141a. Itis to be noted that such a collection operation of a deviation(correction information) as just described is executed each time anoperation mode is changed in a semiautomatic control mode.

Further, if the input switch 141c is opened and the output switch 141dis closed, then deviation information from the storage section 141a isoutputted through the amplifier 141b and added to cylinder targetposition information set by the target value setting means 80.

Consequently, since signals produced taking errors into considerationare inputted as position and velocity control signals to be outputted tothe cylinders 120 to 122, deviations between actual hydraulic cylinderpositions and target cylinder positions can be eliminated, and accurateand reliable tip position control can be performed.

For example, if deviations between target cylinder positions and actualcylinder positions are obtained as such characteristic data asillustrated in FIG. 22(a) upon simulation operation, then informationcorresponding to the deviations illustrated in FIG. 22(a) are added tothe target cylinder position information [indicated by a solid line inFIG. 22(b)] set by the target value setting means 80. Consequently,control signals of such a characteristic as indicated by a broken linein FIG. 22(b) are actually inputted to the hydraulic cylinders 120 to122.

It is to be noted that reference symbols 142a to 142d in the targetvelocity correction information storage means 142 shown in FIG. 21correspond to the storage section 141a, amplifier 141b, input switch141c and output switch 141d described above, respectively, andindividually have functions similar to those of the storage section141a, amplifier 141b, input switch 141c and output switch 141d,respectively.

Further, while the axis of abscissa in FIGS. 22(a) and 22(b) is set asthe stick cylinder position, the axis of abscissa in FIGS. 22(a) and22(b) may be set as the time.

Meanwhile, where deviation information between target cylinder positionsand actual cylinder positions is obtained using the correctioninformation storage means 140 having such a construction as describedabove, since the deviations between the actual cylinder positions andthe target cylinder positions can be reduced to 0, in this instance, thecontribution of PID control by the feedback loop type compensation means73 becomes low. However, it is supposed that the loads to the cylinders120 to 122 during operation in a semiautomatic control mode may vary,and when such a disturbance as just mentioned acts, such control thatthe deviations between the target cylinder positions and the actualcylinder positions are eliminated is performed by the feedback loop typecompensation means 73.

In the control apparatus for a construction machine as the thirdembodiment of the present invention, since the correction informationstorage means 140 for storing correction information for correctingtarget operation information set by the target value setting means 80 isprovided in the controller 1 and the hydraulic cylinders 120 to 122 arecontrolled based on the correction target operation information from thecorrection information storage means 140 so that the operations of theboom 200 and so forth may exhibit target operation conditions, theaccuracy of the tip position control of the bucket 400 can be augmented.

Here, collection and outputting of correction information by thecorrection information storage means 140 are described. First, if anoperator switches the control to semiautomatic control and sets one ofoperation modes such as the slope face excavation mode, then targetcylinder positions and target cylinder velocities corresponding to theoperation mode are set by the target value setting means 80.

Further, in the correction information storage means 140, the inputswitch 141c is closed (switched ON) in synchronism with the changingover operation to the semiautomatic control, and the output switch 141dis opened (switched OFF).

Further, based on control signals of the target cylinder positions andthe target cylinder velocities set by the target value setting means 80,a simulation operation (predetermined operation) of the cylinders 120 to122 for the boom 200 and so forth is executed.

In this instance, while actual cylinder positions and actual cylindervelocities of the hydraulic cylinders 120 to 122 of the boom 200 and soforth are detected by the cylinder position detection means 83, thedetection signals are returned to the input side through the feedbackloop type compensation means 72, and deviations of them from the targetcylinder positions and the target cylinder velocities [refer to FIG.22(a)] are calculated.

Further, since, upon such a simulation operation as described above, theinput switch 141c is ON and the output switch 141d is OFF, the deviationinformation is stored into the storage section 141b of the correctioninformation storage means 140 through the input switch 141c. It is to benoted that the deviations described above are control errors whichappear between the target cylinder positions (velocities) and the actualcylinder positions (velocities) by feedback control and feedforwardcontrol.

Then, if such a simulation operation as described above is executed apredetermined number of times (for example, once), then the input switch141c is now switched OFF while the output switch 141d is switched ON,and an operation by an actual semiautomatic control mode is started.

In this instance, the deviation information stored in the storagesection 141b is outputted through the amplifier 141c and the outputswitch 141d and added to the information from the target value settingmeans 80.

Accordingly, upon actual control, control signals [indicated by a brokenline in FIG. 22(b)) produced from the information from the target valuesetting means 80 taking the deviation information into consideration areoutputted to the hydraulic cylinders 120 to 122, and deviations betweenthe target cylinder positions (velocities) and the actual cylinderpositions (velocities) in actual control can be eliminated to theutmost.

In particular, prior to starting of an operation by a semiautomaticcontrol mode, a simulation mode according to the control mode isperformed, whereupon deviation information between target cylinderpositions (velocities) and actual cylinder positions (velocities) isstored, and upon starting of actual control, the deviation informationis added to the target cylinder position information to correct controlsignals to the hydraulic cylinders 120 to 122.

Accordingly, the control signals corrected taking the deviations intoconsideration are inputted to the hydraulic cylinders 120 to 122, andthe accuracy in position control and velocity control of the hydrauliccylinders 120 to 122 can be augmented remarkably. Consequently, also thecontrol accuracy of the tip position can be augmented remarkably.

Furthermore, with the control apparatus for a construction machine ofthe present invention, also there is an advantage that the increase incost and the increase in weight are little due to the simpleconstruction that the simple circuit of the correction informationstorage means 140 is provided.

(4) Description of the Fourth Embodiment

In the following, a control apparatus for a construction machineaccording to a fourth embodiment is described principally with referenceto FIGS. 24 to 26. It is to be noted that the general construction of aconstruction machine to which the present fourth embodiment is appliedis similar to the contents described above with reference to FIG. 1 andso forth in connection with the first embodiment described above, andthe general construction of a controlling system of the constructionmachine is similar to the contents described above with reference toFIGS. 2 to 4 in connection with the first embodiment described above.Further, the forms of the representative semiautomatic modes of theconstruction machine are similar to the contents described above withreference to FIGS. 9 to 14 in connection with the first embodimentdescribed above. Therefore, description of portions corresponding tothem is omitted, and in the following, description principally ofdifferences from the first embodiment is given.

As described above, the hydraulic excavator is constructed such that atleast the boom 200 (boom cylinder 120) and the stick 300 (stick cylinder121) are controlled by electric controlling systems (feedback loopcontrolling systems) independent of each other using solenoid valves orthe like.

By the way, usually with a hydraulic excavator, where such an operationas to, for example, level the ground flat (slope face formation) is tobe performed, an operation of linearly moving the tip of the bucket 400(that is, the stick 300) is required. However, in such a hydraulicexcavator as mentioned above, since the boom 200 and the stick 300 arecontrolled independently of each other by the hydraulic cylinders 120and 121, respectively, it is very difficult to finish a slope face witha high degree of accuracy.

In particular, where the boom 200 and the stick 300 are electricallyfeedback controlled using solenoid valves or the like as describedabove, if the corresponding hydraulic cylinders 120 and 121 arecontrolled independently of each other, respectively, then even if therespective feedback control deviations are small, the control deviationscannot be ignored depending upon the positions (postures) of the boom200 and the stick 300, and an error from a target tip position (controltarget value) of the bucket 400 sometimes becomes very large.

For example, if control of the boom 200 is delayed with respect to thestick 300 due to the control deviations described above when the bucket400 is at a position at which a slope face is to be formed subsequently,then the tip of the bucket 400 will bite into the ground, but on thecontrary if control of the stick 300 is delayed with respect to the boom200, then the bucket 400 will operate while it remains floating in theair.

In this manner, if the boom 200 and the stick 300 are individuallycontrolled fully independently of each other, then it is very difficultto operate the boom 200 and the stick 300 while maintaining controltarget values.

Thus, the control apparatus for a construction machine of the fourthembodiment of the present invention is constructed such that the armmembers such as the boom 200 and the stick 300 are controlled taking thecontrol deviations upon feedback control into consideration to cause thearm members to always operate in an ideal condition wherein the feedbackdeviation information is reduced to zero so that a predeterminedoperation may be performed with a high degree of accuracy.

In particular, in the present embodiment, the boom 200 and the stick 300are not controlled by feedback controlling systems fully independent ofeach other as in the prior art, but are controlled in a mutuallyassociated condition so that the stick 300 and the tip 112 of the bucket400 may be moved linearly with a high degree of accuracy in the slopeface excavation mode.

It is to be noted that, in the present embodiment, the stick operationlever 8 is used to determine the bucket tip moving velocity in aparallel direction to a set excavation inclined face, and theboom/bucket operation lever 6 is used to determine the bucket tip movingvelocity in a perpendicular direction to the set inclined face.Accordingly, when the stick operation lever 8 and the boom/bucketoperation lever 6 are operated at the same time, the moving directionand the moving velocity of the bucket tip are determined by a compositevector in the parallel and perpendicular directions to the set inclinedface.

Further, in the present embodiment, boom hydraulic cylinderextension/contraction displacement detection means for detectingextension/contraction displacement information of the boom cylinder 120is formed from the signal converter 26 and the resolver 20 which servesas boom posture detection means, and stick hydraulic cylinderextension/contraction displacement detection means for detectingextension/contraction detection means of the stick cylinder 121 isformed from the signal converter 26 and the resolver 21 which serves asstick posture detection means.

Subsequently, a control algorithm of the semiautomatic system performedby the controller 1 is described. A control algorithm of thesemiautomatic control modes (except the packet automatic return mode)performed by the controller 1 is generally such as illustrated in FIG.23, and a construction of essential part of the controller 1 is such asshown in FIG. 24.

It is to be noted that the control algorithm illustrated in FIG. 23 andthe block diagram shown in FIG. 24 are almost same as those describedhereinabove with reference to FIGS. 4 and 5 in the first embodiment, buthave some differences. Therefore, they are described again withreference to FIGS. 23 and 24.

First, the control algorithm illustrated in FIG. 23 is described. First,the moving velocity and direction of the bucket tip 112 are calculatedfrom information of a target slope face set angle, pilot hydraulicpressures which control the stick cylinder 121 and the boom cylinder120, a vehicle inclination angle and an engine rotational speed. Then,target velocities of the cylinders 120, 121 and 122 are calculated basedon the information. In this instance, the information of the enginerotational speed is required to determine an upper limit to the cylindervelocities.

Meanwhile, the controller 1 includes control sections 1A, 1B and 1C forthe cylinders 120, 121 and 122, and the individual controls are formedas control feedback loops as shown in FIG. 23.

The compensation construction in the closed loop controls shown in FIG.23 has, in each of the control sections 1A, 1B and 1C, a multiplefreedom degree construction of a feedback loop and a feedforward loopwith regard to the displacement and the velocity as shown in FIG. 24,and includes feedback loop type compensation means 72 having a variablecontrol gain (control parameter), and feedforward type compensationmeans 73 having a variable control gain (control parameter).

In particular, if a target velocity is given, then with regard to thefeedback loop process, feedback loop processes according to a routewherein a deviation between the target velocity and velocity feedbackinformation is multiplied by a predetermined gain Kvp (refer toreference numeral 62), another route wherein the target velocity isintegrated once (refer to an integration element 61 of FIG. 24) and adeviation between the target velocity integration information anddisplacement feedback information is multiplied by a predetermined gainKpp (refer to reference numeral 63) and a further route wherein thedeviation between the target velocity integration information and thedisplacement feedback information is multiplied by a predetermined gainKpi (refer to reference numeral 64) and further integrated (refer toreference numeral 66) are performed while, with regard to thefeedforward loop process, a process by a route wherein the targetvelocity is multiplied by a predetermined gain Kf (refer to referencenumeral 65) is performed.

Of the processes, the feedback loop processes are described in a littlemore detail. In the present apparatus, operation information detectionmeans 91 for detecting operation information of the cylinders 120 to 122is provided, and the controller 1 receives the detection informationfrom the operation information detection means 91 and target operationinformation (for example, target moving velocities) set by the targetvalue setting means 80 as input information and sets control signals sothat the arm members such as the boom 200 and the working member(bucket) 400 may exhibit target operation conditions.

It is to be noted that, while the operation information detection means91 particularly is posture information detection means 83 for detectingthe postures of the boom 200 and the stick 300, the posture informationdetection means 83 also has a function as operation condition detectionmeans 90, which will be hereinafter described, and detection means 93 iscomposed of the operation information detection means 91 and theoperation condition detection means 90 which is hereinafter described.

Meanwhile, the values of the gains Kvp, Kpp, Kpi and Kf mentioned abovecan individually be varied by the gain scheduler (control parameterscheduler) 70, and the values of the gains Kvp, Kpp, Kpi and Kf arevaried or corrected in this manner to control the boom 200, the bucket400 and so forth to target operation conditions.

In particular, the present apparatus includes, as shown in FIG. 24,operation condition detection means 90 which in turn includes oiltemperature detection means 81 for detecting an oil temperature of theoperating oil, cylinder load detection means 82 for detecting the loadsto the cylinders 120 to 122, and cylinder position detection means 83for detecting position information of the cylinders. The gain scheduler70 varies the gains Kvp, Kpp, Kpi and Kf based on detection informationfrom the operation condition detection means 90 (that is, operationinformation of the construction machine).

Of the means, the oil temperature detection means 81 is temperaturesensors provided in the proximity of the solenoid proportional valves3A, 3B and 3C, and the gain scheduler 70 corrects the gains in responseto a temperature relating to the cylinders 120 to 122. It is to be notedthat the temperature relating to the cylinders 120 to 122 signifies, forexample, the temperature of controlling oil (pilot oil), and here, thetemperature of the pilot oil is detected as the representative oiltemperature which represents the temperature of the operating oil.

Further, while, as shown in FIG. 24, a non-linearity removal table 71 isprovided to remove non-linear properties of the solenoid proportionalvalves 3A to 3C, the main control valves 13 to 15 and so forth, aprocess in which the non-linearity removal table 71 is used is performedat a high speed by a computer using a table lookup technique.

By the way, as shown in FIG. 25, in the present embodiment, a feedbackcontrol deviation (feedback deviation information) of a stickcontrolling system (second controlling system) 1B' is supplied to a boomcontrolling system (first controlling system) 1A' while a feedbackcontrol deviation of the boom controlling system 1A' is supplied to thestick controlling system 1B', and the controlling systems 1A' and 1B'perform correction of control target values (positions and velocities)of the boom/cylinder based on the feedback control deviations.

To this end, the controller 1 includes, as shown in FIG. 25, in additionto the boom controlling system 1A' and the stick controlling system 1B'described above, a boom (first) correction value generation section 111Aand a boom (first) weight coefficient addition section 112A as a boom(first) correction controlling system 11A for correcting control targetvalues of the boom controlling system 1A' based on the feedback controldeviations of the stick controlling system 1B', and a stick (second)correction value generation section 111B and a boom (second) weightcoefficient addition section 112B as a stick (second) correctioncontrolling system 11B for correcting control target values of the stickcontrolling system 1B' based on the feedback control deviations of theboom controlling system 1A'.

Here, the boom correction value generation section 111A generates boomcorrection values (boom modification amounts) for correcting controltarget values of the boom cylinder 120 of the boom controlling system1A' from the feedback control deviations (which may be hereinafterreferred to merely as control deviations) of the stick controllingsystem 1B'. Here, the boom correction value generation section 111A isset such that it increases its boom correction values substantially inproportion to the magnitudes of the control deviations from the stickcontrolling system 1B', which is the other controlling system), as shownin FIG. 25.

Meanwhile, the stick correction value generation section 111B generatesboom correction values for correcting the control target values of thestick cylinder 121 of the stick controlling system 1B' from the controldeviations of the boom controlling system 1A'. The stick correctionvalue generation section 111B is set such that, similarly to the boomcorrection value generation section 111A described above, it increasesits boom correction values substantially in proportion to the magnitudesof the control deviations from the boom controlling system 1A' which isthe other controlling system.

Further, the bucket tip boom weight coefficient addition section 112Aand the stick weight coefficient addition section 112B add weightcoefficients to the boom correction values and the stick correctionvalues generated by the corresponding boom correction value generationsection 111A and stick correction value generation section 111B,respectively. Here, for example, as shown in FIG. 26, the boomcorrection values are multiplied by a boom weight coefficient havingsuch a characteristic as indicated by a solid line (a characteristicwherein the positive or negative polarity of a coefficient to be addedis reversed in response to the distance between the tip position of thebucket 400 and the construction machine body 100) by the boom weightcoefficient addition section 112A while the stick correction values aremultiplied by a stick weight coefficient having such a characteristic asindicated by a broken line (a characteristic substantially opposite tothat of the boom weight coefficient) by the stick weight coefficientaddition section 112B.

Consequently, the correction controlling systems 11A and 11B can varycorrection values for correcting control target values of thecontrolling systems 1A' and 1B' and can effect correction of controltarget values flexibly. It is to be noted that, while such a weightcoefficient addition section 112A (112B) as described above may beprovided only one of the correction controlling systems 11A and 11B,here it is provided for both of the correction controlling systems 11Aand 11B so that cancellation of control deviations which will behereinafter described can be performed at a high speed.

In the following, correction processing of control target values by thecontroller 1 having the construction described above is described. Forexample, if, in the slope face excavation mode (bucket tip linearexcavation mode), control of the boom 200 (boom cylinder 120) is delayedfrom control of the stick 300 (stick cylinder 121) when the tip positionof the bucket 400 is positioned at a location near the constructionmachine body 100, then the operation velocity of the stick 300relatively increases and a control deviation is produced with the stickcontrolling system 1B'.

The control deviation is inputted to the boom correction valuegeneration section 111A of the boom correction controlling system 11A,and the boom correction value generation section 111A generates a boomcorrection value for raising the control target value of the boomcylinder 120. Now, since the tip position of the bucket 400 ispositioned at a location near the construction machine body 100, theboom correction value is multiplied by the boom weight coefficientaddition section 112A by such a positive weight coefficient whichincreases the value of the boom correction value (refer to a solid linein FIG. 26).

Then, the boom correction value multiplied by the weight coefficient inthis manner is added to the target value of the boom cylinder 120. As aresult, the operation speed of the boom cylinder 120 increases.

Meanwhile, in this instance, the control error produced with the boomcontrolling system 1A' is inputted to the stick correction valuegeneration section 111B of the stick correction controlling system 11B.The stick correction value generation section 111B generates a stickcorrection value for decreasing the control target value of the stickcylinder 121 contrary to the boom correction value generation section111A described above. Now, however, since the tip position of the bucket400 described above is positioned at a location near the constructionmachine body 100, the stick correction value is multiplied by the stickweight coefficient addition section 112B by such a negative weightcoefficient which decreases the value of the stick correction value(refer to a broken line in FIG. 26).

Then, the stick correction value multiplied by the weight coefficient inthis manner is added to the target value of the stick cylinder 121. As aresult, the operation velocity of the stick cylinder 121 decreases.

Consequently, the control error of the boom controlling system 1A' andthe control error of the stick controlling system 1B' cancel each other,and the boom 200 and the stick 300 can perform a linear excavationoperation in the slope face excavation mode (bucket tip linearexcavation mode) stably with a high degree of accuracy.

It is to be noted that, if control of the boom 200 (boom cylinder 120)is delayed from control of the stick 300 (stick cylinder 121) when thetip position of the bucket 400 is positioned at a location far from theconstruction machine body 100, then also the operation velocity of thestick 300 is delayed. In this instance, however, since the boomcorrection value is multiplied by a negative weight coefficient by theboom weight coefficient addition section 112A and the boom correctionvalue is multiplied by a positive weight coefficient by the stick weightcoefficient addition section 112B, the operation velocity of the stickcylinder 121 relatively increases and the control deviations cancel eachother.

In short, the controller 1 described above is constructed such that,when it controls the boom 200 and the stick 300 individually, while itcorrects control target values of the self controlling systems 1A' and1B' thereof based on control deviations of the controlling systems 1B'and 1A' other than the self controlling systems, it controls the boom200 and the stick 300 in a mutually associated relationship so that theboom 200 and the stick 300 may operate always in an ideal conditionwherein control deviations of the controlling systems 1A' and 1B' areeliminated.

Since the control apparatus for a construction machine as the fourthembodiment of the present invention is constructed in such a manner asdescribed above, when such a slope face excavation operation of a targetslope face angle α as shown in FIG. 13 is performed semiautomaticallyusing the hydraulic excavator, such semiautomatic controlling functionsas described above can be realized. In particular, detection signals(including setting information of a target slope face angle) from thevarious sensors are inputted to the controller 1, and the controller 1controls the main control valves 13, 14 and 15 through the solenoidproportional valves 3A, 3B and 3C based on the detection signals fromthe sensors (including also detection signals of the resolvers 20 to 22received through the signal converter 26) to effect such control thatthe boom 200, stick 300 and bucket 400 may exhibit desiredextension/contraction displacements to execute such semiautomaticcontrol as described above.

Then, upon the semiautomatic control, the moving velocity and directionof the bucket tip 112 are calculated from information of the targetslope face set angle, pilot hydraulic pressures which control the stickcylinder 121 and the boom cylinder 120, a vehicle inclination angle andan engine rotational speed, and target velocities of the cylinders 120,121 and 122 are calculated based on the information. The information ofthe engine rotational speed then is required to determine an upper limitto the cylinder velocities.

Further, the control in this instance is performed by a feedback loopfor each of the cylinders 120, 121 and 122, and in the presentembodiment, as described hereinabove, when the boom 200 (boom cylinder120) and the stick 300 (stick cylinder 121) are to be individuallycontrolled, while the control target values of the self controllingsystems 1A' and 1B' of the boom 200 and the stick 300 are corrected bythe correction controlling systems 11A and 11B, respectively, based oncontrol deviations of the controlling systems 1B' and 1A' other than theself controlling systems, the boom 200 and the stick 300 are controlledin a mutually associated relationship so that the boom 200 and the stick300 may operate always in an ideal condition wherein control deviationsof the controlling systems 1A' and 1B' are eliminated.

As described in detail above, with the control apparatus for aconstruction machine as the present embodiment, since the boom 200 (boomcylinder 120) and the stick 300 (stick cylinder 121) are not controlledby feedback controlling systems fully independent of each other as inthe prior art but, while control target values of the self controllingsystems 1A' and 1B' are corrected by the correction controlling systems11A and 11B based on control deviations of the controlling systems 1B'and 1A' other than the self controlling system, the boom 200 and thestick 300 are controlled in a mutually associated relationship so thatthe boom 200 and the stick 300 are operated always in an ideal conditionwherein control deviations of the controlling systems 1A' and 1B' areeliminated, any construction operation (particularly an operation in thebucket tip linear excavation mode) can be performed with a very highdegree of accuracy, and the finish accuracy in operation can beaugmented remarkably.

Furthermore, in the present embodiment, since posture information of theboom 200 and the stick 300 can be detected simply by detectingextension/contraction displacement information of the hydrauliccylinders 120 and 121, respectively, using the resolvers 20 and 21 andthe signal converter 26, the posture information of the boom 200 and thestick 300 can be obtained accurately with a simple construction.

Further, as described with reference to FIG. 25, since a boom correctionvalue for correcting a control target value of the boom controllingsystem 1A' and a stick correction value for correcting a control targetvalue of the stick controlling system 1B' can be generated to effectcorrection of the control target values of the boom cylinder 120 and thestick cylinder 121 with certainty with such a simple construction thatthe boom correction value generation section 111A is provided in theboom correction controlling system 11A and the stick correction valuegeneration section 111B is provided in the stick correction controllingsystem 11B, also the reliability upon correction processing isaugmented.

Furthermore, since the boom weight coefficient addition section 112A isprovided in the boom correction controlling system 11A and the stickweight coefficient addition section 112B is provided in the stickcorrection controlling system 11B so that the correction values can bevaried in accordance with the necessity, correction of control targetvalues of the boom cylinder 120 and the stick cylinder 121 can beperformed flexibly, and appropriate correction and control can always beperformed at a high speed in whichever conditions (postures) the boom200 and the stick 300 are. It is to be noted that such a weightcoefficient addition section 112A (112B) as just described may beprovided for only one of the correction controlling systems 11A and 11B.

(5) Description of the Fifth Embodiment

In the following, a control apparatus for a construction machineaccording to a fifth embodiment is described principally with referenceto FIGS. 27 and 28. It is to be noted that the general construction of aconstruction machine to which the present fifth embodiment is applied issimilar to the contents described hereinabove with reference to FIG. 1and so forth in connection with the first embodiment described above,and the general construction of controlling systems of the constructionmachine is similar to the contents described hereinabove with referenceto FIGS. 2 to 4 in connection with the first embodiment described above.Further, the forms of representative semiautomatic modes of theconstruction machine are similar to the contents described hereinabovewith reference to FIGS. 9 to 14 in connection with the first embodimentdescribed above. Therefore, description of portions corresponding tothem is omitted, and in the following, description principally ofdifferences from the first embodiment is given.

Generally, in a construction operation by a hydraulic excavator, anoperation (called bucket tip linear excavation mode) of moving the tipof the bucket 400 linearly such as horizontal leveling (slope faceformation) of the ground is sometimes required. In this instance, with acontrol apparatus for the hydraulic excavator, the operation describedabove is realized by feedback controlling the boom 200 (hydrauliccylinder 120) and the stick 300 (hydraulic cylinder 121) electricallyindependently of each other individually using solenoid valves or thelike.

In particular, for example, target positions (control target values) ofthe hydraulic cylinders 120 and 121 are determined by a predeterminedcalculation based on a target bucket tip position obtained fromoperation positions of operation levers (hereinafter referred to asstick operation levers) for the stick 300, and the hydraulic cylinders120 and 121 are individually feedback controlled independently of eachother based on the obtained target values.

In a conventional control apparatus for a hydraulic shovel, since thehydraulic cylinders 120 and 121 are individually feedback controlledindependently of each other based on control target values obtained froma target bucket tip position, for example, if it is tried to draw thestick 300 toward the construction machine body 100 side to linearly movethe tip of the bucket 400 from a condition wherein the bucket 400 ispositioned far from the construction machine body 100, then if theposition deviation of the boom 200 is small (the delay is little) andthe position deviation of the stick 300 is large (the delay is much),then a condition wherein the actual tip position of the bucket 400 isdisplaced upwardly from a target position (target slope face) isentered, and as a result, there is a subject that the finish accuracy ofthe slope face is deteriorated significantly.

Therefore, the control apparatus for a construction machine of the fifthembodiment of the present invention is constructed such that theoperation of an arm member (boom or stick) is controlled while theactual position (posture) of the arm member is taken into consideration,thereby achieving augmentation of the accuracy in predeterminedconstruction operation.

First, a general construction of the control apparatus for aconstruction machine of the present embodiment is described. The presentcontrol apparatus for a construction machine includes, similarly to theembodiments described above, hydraulic circuits for the cylinders 120 to122, hydraulic motors and a revolving motor. In the hydraulic circuits,pumps 51 and 52 which are driven by an engine 700, main control valves(control valves) 13, 14 and 15 and so forth are interposed (refer toFIG. 2).

Further, in the present embodiment, for the hydraulic circuits,hydraulic circuits of the open center type wherein theextension/contraction displacement velocities of the cylinder 120 to 122rely upon the loads acting upon the cylinder 120 to 122 (for example,the extension/contraction displacement velocities become lower inresponse to the force received from the ground upon an excavationoperation) are applied.

Meanwhile, a stick operation lever 8 is used to determine the bucket tipmoving velocity in a parallel direction with respect to a set excavationinclined face, and a boom/bucket operation lever 6 is used to determinethe bucket tip moving velocity in a perpendicular direction to the setinclined face. Accordingly, when the stick operation lever 8 and theboom/bucket operation lever 6 are operated at the same time, the movingdirection and the moving velocity of the bucket tip are determined by acomposite vector in the parallel direction and the perpendiculardirection with respect to the set inclined face.

Further, in the present embodiment, extension/contraction displacementdetection means for detecting extension/contraction displacementinformation of the boom hydraulic cylinder 120 is composed of a signalconverter 26 and a resolver 20 which serves as boom posture detectionmeans (or arm member posture detection means), and extension/contractiondisplacement detection means for detecting extension/contractdisplacement information of the hydraulic cylinder 121 is composed ofthe signal converter 26 and a resolver 21 which serves as stick posturedetection means (or arm member posture detection means).

In the following, a construction of essential part of the presentembodiment is described. In the present embodiment, when the controller1 calculates target velocities of the boom cylinder 120 and the stickcylinder 121, the target speed of the boom is determined taking actualpostures of the boom 200 and the stick 300 into consideration so that alinear operation of the bucket tip 112 particularly in the slope faceexcavation mode may be performed with a high degree of accuracy.

To this end, the controller 1 of the present embodiment includes, forexample, as shown in FIG. 27, a target bucket tip position detectionsection 31, a calculation target stick position setting section (stickcontrol target value setting means) 32, a calculation target boomposition setting section (boom control target value setting means) 33,an actual boom control target value calculation section (actual controltarget value calculation means) 34 and a composite target boom positioncalculation section (composite control target value calculation means orcomposite boom control target value calculation means) 35. It is to benoted that closed loop control sections 1A and 1B are constructed in asimilar manner to those shown in FIGS. 3, 4 and 24.

Here, the target bucket tip position detection section 31 detectsoperation position information of the boom/bucket operation lever (armmechanism operation member) 6, and the calculation target stick positionsetting section (stick control target value setting means) 32 determinesa target stick position (stick control target value) for stick controlby a predetermined calculation from the operation position informationdetected by the target bucket tip position detection section 31.

In particular, the calculation target stick position setting section 32determines, by calculation processing described below, a calculationtarget stick position (stick cylinder length) λ_(103/105) from a targetbucket tip position (x₁₁₅, y₁₁₅) as operation position information ofthe operation lever 6 obtained by the target bucket tip positiondetection section 31 (refer to FIG. 8). It is to be noted that L_(i/j)represents a fixed length, λ_(i/j) a variable length, A_(i/j/k) a fixedangle, and θ_(i/j/k) represents a variable angle, the suffix i/j to Lrepresents the length between nodes i and j, the suffix i/j/k to A and θrepresents to connect the nodes i, j and k in order of i→j→k.Accordingly, for example, L_(101/102) represents the distance betweenthe node 101 and the node 102, and θ_(103/104/105) represents the angledefined when the nodes 103 to 105 are connected in order of the node103→node 104→node 105. Further, also here, the node 101 is assumed to bethe origin of the xy coordinate system as shown in FIG. 8.

First, the calculation target stick position is represented by thefollowing expression (2-1) in accordance with the cosine theorem.

    λ.sub.103/105 =(L.sub.103/104.sup.2 +L.sub.104/105.sup.2 -2L.sub.103/104 ·L.sub.104/105 ·cos θ.sub.103/104/105).sup.1/2                          (2-1)

Here, since L_(103/104) and L_(104/105) given above are individuallyknown fixed values, if θ_(103/104/105) is determined, then the stickposition λ_(103/105) can be determined. From FIG. 8, θ_(103/104/105) canbe represented as

    θ.sub.103/104/105 =2π-A.sub.105/104/108 -A.sub.101/104/103 -θ.sub.101/104/115 -θ.sub.108/104/115         (2-2)

Now, since A_(105/104/108) and A_(101/104/103) above are individuallyfixed angles, θ_(101/104/115) and θ_(108/104/115) should be determined.

First, θ_(101/104/105) can be represented, in accordance with the cosinetheorem, as

    θ.sub.101/104/115 =cos.sup.-1 [(L.sub.101/104.sup.2 +L.sub.104/115.sup.2 -λ.sub.101/115.sup.2)/2L.sub.101/104 ·L.sub.104/115 ]                                 (2-3)

Here, λ_(101/115) =(x₁₁₅ ² +y₁₁₅ ²)^(1/2), and x₁₁₅ and y₁₁₅ areindividually known values obtained by the target bucket tip positiondetection section 31.

Meanwhile, θ_(108/104/115) can be represented, in accordance with thecosine theorem, as

    θ.sub.108/104/115 =cos.sup.-1 [(L.sub.104/108.sup.2 +λ.sub.104/115.sup.2 -L.sub.108/115.sup.2)/2L.sub.104/108 ·λ.sub.104/115 ]                          (2-4)

Here, since λ_(104/115) above can be represented as:

    λ.sub.104/115 =(L.sub.104/108.sup.2 +L.sub.108/115.sup.2 -2L.sub.104/108 ·L.sub.108/115 ·cos θ.sub.104/108/115).sup.1/2                          (2-5)

Further, θ_(104/108/115) in the present expression (2-5) is representedas

    θ.sub.104/108/115 =2π-A.sub.110/108/115 -A.sub.104/108/107 -θ.sub.107/108/110                                  (2-6)

And θ_(107/108/110) in this expression (2-6) is represented as

    θ.sub.107/108/110 =θ.sub.107/108/109 +θ.sub.109/108/110 ( 2-7)

Then, θ_(107/108/109) and θ_(109/108/110) in the present expression(2-7) are represented, in accordance with the cosine theorem, as

    θ.sub.107/108/109 =cos.sup.-1 [(L.sub.107/108.sup.2 +λ.sub.108/109.sup.2 -L.sub.107/109.sup.2)/2L.sub.107/108 ·λ.sub.108/109 ]                          (2-8)

    θ.sub.109/108/110 =cos.sup.-1 [(L.sub.108/110.sup.2 +λ.sub.108/109.sup.2 -L.sub.109/110.sup.2)/2L.sub.108/110 ·λ.sub.108/109 ]                          (2-9)

respectively. Here, λ_(108/109) in the expressions (2-8) and (2-9) isrepresented, in accordance with the cosine theorem, as

    λ.sub.108/109 =(L.sub.107/109.sup.2 +L.sub.107/108.sup.2 -2L.sub.107/109 ·L.sub.107/108 ·cos θ.sub.108/107/109).sup.1/2                          (2-10)

Since θ_(108/107/109) in the present expression (2-10) is the bucketangle as can be seen from FIG. 8, if it is assumed that the angleinformation detected by the resolver 22 described above which plays thefunction as a bucket angle sensor is this θ_(108/107/109), then theunknown values are successively settled in accordance with theexpressions (2-4) to (2-10) given above, and consequently,θ_(108/104/115) in the expression (2-3) is settled.

Accordingly, θ_(103/104/105) represented by the expression (2-2) issettled, and finally, the calculation target stick position λ_(103/105)represented by the expression (2-1) is settled. It is to be noted that,in the present embodiment, since the angle information detected by theresolver 22 is converted into extension/contraction displacementinformation of the hydraulic cylinder 122 by the signal converter 26,θ_(108/107/109) in the expression (2-10) above may be determined fromthe bucket cylinder length in place of the angle information.

In this instance, from FIG. 8, θ_(108/107/109) can be represented as

    θ.sub.108/107/109 =2π-A.sub.105/107/108 -A.sub.105/107/106 -θ.sub.106/107/109                                  (2-11)

Here, θ_(106/107/109) in the present expression (2-11) can berepresented, in accordance with the cosine theorem, as

    θ.sub.106/107/109 =cos.sup.-1 [(L.sub.106/107.sup.2 +L.sub.107/109.sup.2 -λ.sub.106/109.sup.2)/2L.sub.106/107 ·λ.sub.107/109 ]                          (2-12)

Since λ_(106/109) is the bucket cylinder length obtained fromextension/contraction displacement information of the hydraulic cylinder122, θ_(108/107/109) represented by the expression (2-11) is settled,and thereafter, the calculation target stick position λ_(103/105) isdetermined in accordance with the expressions (2-1) to (2-10) in asimilar manner.

Subsequently, the calculation target boom position setting section (boomcontrol target value setting means) 33 described above is described. Thecalculation target boom position setting section 33 determines acalculation target boom position (boom control target value) for boomcontrol from operation position information detected by the targetbucket tip position detection section 31 by a predetermined calculation,and calculation control target value setting means is composed of thetarget bucket tip position detection section 31 and the calculationtarget boom position setting section 33. Then, here, the calculationtarget boom position (boom cylinder length) λ_(102/111) (refer to FIG.8) is determined by such calculation processing as described below.

The calculation target boom position λ_(102/111) can be represented as

    λ.sub.102/111 =(L.sub.101/102.sup.2 +L.sub.101/111.sup.2 -2L.sub.101/102 ·L.sub.101/111 ·cos θ.sub.102/101/111).sup.1/2                          (2-13)

Here, θ_(102/101/111) in the present expression (2-13) can berepresented as

    θ.sub.102/101/111 =Axbm+θbm                    (2-14)

θbm in this expression (2-14) can be represented as

    θbm=A.sub.102/101/104 +θ.sub.104/101/115 +tan.sup.-1 (y.sub.115 /x.sub.115)                                               (2-15)

Further, θ_(104/101/115) in the present expression (2-15) can berepresented as

    θ.sub.104/101/115 =cos.sup.-1 [L.sub.101/104.sup.2 +λ.sub.101/115.sup.2 -λ.sub.104/115.sup.2)/2L.sub.101/104 ·λ.sub.101/115 ]                          (2-16)

Here, λ_(101/115) in the present expression (2-16) can be represented as

    λ.sub.101/115 =(x.sub.115.sup.2 +y.sub.115.sup.2).sup.1/2(2-17)

If the target bucket tip position (x₁₁₅, y₁₁₅) as the operation positioninformation detected by the target bucket tip position detection section31 is substituted into x₁₁₅, y₁₁₅ of the present expression (2-17), thenthe calculation target boom position λ_(102/111) can be determined inaccordance with the expressions (2-13) to (2-16). It is to be notedthat, for λ_(104/115), the value calculated in accordance with theexpression (2-5) is used.

Further, the actual boom control target value calculation section 34described above calculates an actual target boom position (actual boomcontrol target value) for boom control from actual posture informationof the boom 200 and the stick 300. To this end, the actual boom controltarget value calculation section 34 includes an actual bucket tipposition calculation section 34A and an actual target boom positioncalculation section (actual boom control target value calculationsection) 34B.

Here, the actual bucket tip position calculation section 34A determinesthe actual tip position of the bucket 400 (actual bucket tip position)by calculation from the actual positions of the boom cylinder 120, stickcylinder 121 and bucket cylinder 122 (extension/contraction displacementinformation of the cylinder 120 to 122), that is, actual postureinformation of the boom 200 and the stick 300. Here, the actual buckettip position calculation section 34A determines the actual bucket tipposition (x₁₁₅, y₁₁₅ : refer to FIG. 8) from the actual boom cylinderposition (λ_(102/111)) and stick cylinder position (λ_(103/105)) by suchcalculation processing as described below.

First, since x₁₁₅ and y₁₁₅ can be represented as

    x.sub.115 =λ.sub.101/105 ·cos θbt    (2-18)

    y.sub.115 =λ.sub.101/105 ·sin θbt    (2-19)

respectively, if θbt in the expressions (2-18) and (2-19) is calculated,then the actual bucket tip position can be determined. Here, since thisθbt can be represented as

    θbt=θbm-θ.sub.104/101/115                (2-20)

θbm and θ_(104/101/115) should be determined. Therefor, θ_(104/101/115)is determined first. This θ_(104/101/115) can be represented, from FIG.8, as

    θ.sub.104/101/115 =cos.sup.-1 [L.sub.101/104.sup.2 +λ.sub.101/115.sup.2 -λ.sub.104/115.sup.2)/2L.sub.101/104 ·λ.sub.101/115 ]                          (2-21)

Then, λ_(101/115) in this expression (2-21) can be represented as

    λ.sub.101/115 =(L.sub.101/104.sup.2 +L.sub.104/115.sup.2 -2L.sub.104/115 ·λ.sub.104/115 ·cos θ.sub.101/104/115).sup.1/2                          (2-22)

Further, θ_(101/104/115) in this expression (2-22) can be represented as

    θ.sub.101/104/115 =2π-A.sub.101/104/103 -A.sub.105/104/108 -θ.sub.108/104/115 -θ.sub.103/104/105         (2-23)

It is to be noted that λ_(104/115) in the expression (2-22) above can bedetermined in accordance with the expression (2-5) given hereinabove,and θ_(108/104/115) in the expression (2-23) above can be determined inaccordance with the expression (2-4) given hereinabove. Further,θ_(103/104/105) which is unknown in the expression (2-23) above can becalculated as

    θ.sub.103/104/105 =cos.sup.-1 [L.sub.103/104.sup.2 +L.sub.104/105.sup.2 -λ.sub.103/105.sup.2)/2L.sub.103/104 ·L.sub.104/105 ]                                 (2-24)

Here, since it can be seen that λ_(103/105) given above is the stickcylinder length (actual stick cylinder position) from FIG. 8, if thisstick cylinder length is determined from extension/contractiondisplacement information obtained by conversion by the signal converter26 of actual angle information of the stick 300 obtained by the resolver21, then θ_(103/104/105) is settled in accordance with the expression(2-24), and as a result, the unknowns in the expressions (2-22) to(2-23) are settled successively and θ_(104/101/115) represented by theexpression (2-21) is settled.

Meanwhile, θbm in the expression (2-20) given above can be represented,from FIG. 8, as

    θbm=θ.sub.102/101/111 -A.sub.102/101/104 -Axbm (2-25)

Further, θ_(102/101/111) in this expression (2-25) can be represented,in accordance with the cosine theorem, as

    θ.sub.102/101/111 =cos.sup.-1 [L.sub.101/102.sup.2 +L.sub.101/111.sup.2 -λ.sub.102/111.sup.2)/2L.sub.101/102 ·L.sub.101/111 ]                                 (2-26)

Here, since λ_(102/111) in this expression (2-26) is the boom cylinderlength (actual boom cylinder position), if this boom cylinder length isdetermined from extension/contraction information obtained by conversionby the signal converter 26 of actual angle information of the boom 200obtained by the resolver 20, then θ_(102/101/111) is settled inaccordance with the expression (2-26), and as a result, θbm representedby the expression (2-25) is settled.

Consequently, θbm and θ_(104/101/115) in the expression (2-20) aresettled, and finally, the actual bucket tip position (x₁₁₅, y₁₁₅) isdetermined from the expressions (2-18) and (2-19).

Further, the actual target boom position calculation section (actualboom control target value calculation section) 34B determines the actualtarget boom position mentioned hereinabove from tip position informationof the bucket 400 obtained by the actual bucket tip position calculationsection 34A. It is to be noted that the actual target boom position isdetermined by performing calculation processing [refer to theexpressions (2-13) to (2-17)] similar to that of the calculation targetboom position setting section 33 using the actual target boom positionobtained by the actual bucket tip position calculation section 34A.

The composite target boom position calculation section (compositecontrol target value calculation means or composite control target valuecalculation means) 35 determines a composite target boom position(composite boom control target value) from the actual target boomposition obtained by the actual target boom position calculation section34B and the calculation target boom position obtained by the calculationtarget boom position setting section 33.

Then, in the present embodiment, the boom cylinder 120 is feedbackcontrolled based on the composite target boom position obtained by thecomposite target boom position calculation section 35 by a boomcontrolling system 1A' which is composed of the control section 1A andthe boom cylinder 120 so that the boom 200 may assume a predeterminedposture.

In particular, in the present embodiment, a stick controlling system 1B'feedback controls the hydraulic cylinder 121 based on a target stickposition and extension/contraction displacement information (postureinformation) of the stick 300 detected by the resolver 21 which servesas stick posture detection means, and the boom controlling system 1A'feedback controls the boom cylinder 120 based on a composite target boomposition and extension/contraction displacement information (postureinformation) of the boom 200 detected by the resolver 20 which serves asboom posture detection means so that the boom 200 may assume apredetermined posture.

However, since, in the feedback controls, velocity information isreceived as an input as shown in FIG. 24, position information such asthe bucket tip position and the stick/boom positions described above isused after conversion into velocity information by performingdifferentiation processing or the like.

Consequently, the controller 1 can control the boom cylinder 120 basedon a composite target boom position obtained by composing an idealcalculation target stick position and calculation target boom position(ideal target values for controlling the boom 200 and the stick 300 torespective target postures) obtained by calculation from operationposition information of the boom/bucket operation lever 6 and an actualtarget boom position determined from actual postures of the boom 200 andthe stick 300 and taking the actual postures into consideration, and cancontrol the posture of the boom 200 simply and conveniently while alwaystaking the actual postures of the boom 200 and the stick 300 intoconsideration automatically.

Here, more particularly, the composite target boom position calculationsection 36 described above determines a composite target boom positionby adding predetermined weight information to an actual target boomposition obtained by the actual target boom position calculation section34B and a boom control target value obtained by the calculation targetboom position setting section 33. Here, as shown in FIG. 27, a weightcoefficient "W" (first coefficient: where 0≦W≦1) is added (multiplied)to the calculation target boom position while another weight coefficient"1-W" (second coefficient) is added (multiplied) to the actual targetboom position to determine a composite target boom position.

In short, the weight coefficients mentioned above are set so as to havevalues equal to or larger than 0 but equal to or lower than 1 andbesides exhibit a sum value of 1. Accordingly, it can be varied simplyto which one of the calculation target boom position and the actualtarget boom position importance should be attached, and by setting onlyone "W" of the weight coefficients, it can be set to which one of thecalculation target boom position and the actual target boom positionimportance should be attached.

It is to be noted that the weight coefficient "W" described above is setin the present embodiment so that, for example, as schematicallyillustrated in FIG. 28, it decreases as the length of the hydrauliccylinder 121 increases (as the extension amount increases), that is, asthe stick 300 approaches the construction machine body 100, andconsequently, the composite target boom position calculation section 36determines a composite target boom position attaching increasingimportance to the actual target boom position as the distance of thestick 300 from the construction machine body 100 increases.

Accordingly, for example, when such an operation as to gradually movethe boom 200 downwardly as the bucket 400 (stick 300) approaches theconstruction machine body 100 is performed in order to linearly move thebucket tip 112 of the bucket 400 in the slope face excavation mode, boomcontrol is performed attaching importance to the actual target boomposition obtained taking the actual tip position of the bucket 400(actual postures of the boom 200 and stick 300) into consideration, andsuch a phenomenon that the boom 200 moves down rapidly from thecalculation target boom position due to its weight and the movement ofthe tip position of the bucket 400 is disordered can be prevented withcertainty.

Since the control apparatus for a construction machine as the fifthembodiment of the present invention is constructed in such a manner asdescribed above, when such a slope face excavation operation of a targetslope face angle α as shown in FIG. 13 is performed semiautomaticallyusing the hydraulic excavator, such semiautomatic controlling functionsas described above can be realized. In particular, detection signals(including setting information of the target slope face angle) from thevarious sensors are inputted to the controller 1 incorporated in thehydraulic excavator, and the controller 1 controls the main controlvalves 13, 14 and 15 through the solenoid proportional valves 3A, 3B and3C based on the detection signals from the sensors (including alsodetection signals of the resolvers 20 to 22 received through the signalconverter 26) to effect such control that the boom 200, stick 300 andbucket 400 may exhibit desired extension/contraction displacements toexecute such semiautomatic control as described above. Then, upon thesemiautomatic control, the moving velocity and direction of the buckettip 112 are calculated from information of the target slope face setangle, pilot hydraulic pressures which control the stick cylinder 121and the boom cylinder 120, a vehicle inclination angle and an enginerotational speed, and target velocities of the cylinders 120, 121 and122 are calculated based on the information.

However, in the present embodiment, in this instance, a target velocity(target position) of the boom is determined taking the actual posturesof the boom 200 and the stick 300 into consideration as described abovewith reference to FIG. 27. In particular, a target calculation targetstick position and calculation target boom position are determined fromoperation position information of the operation lever 6 and an actualtarget boom position is determined taking the actual postures of theboom 200 and the stick 300 into consideration, and the positioninformation is composed to determine a composite target boom position.Then, the controller 1 feedback controls the hydraulic cylinder 120based on the composite target boom position.

As described above, in the system according to the present embodiment,since the boom cylinder 120 is controlled by the controller 1 based on acomposite target boom position obtained by composition of idealcalculation target boom/stick positions and actual target boom positionsobtained taking the actual postures of the boom 200 and the stick 300into consideration, while the actual postures of the boom 200 and thestick 300 are automatically taken into consideration, the posture of theboom can be controlled simply and conveniently.

Accordingly, since it is required at least to control the hydrauliccylinder 120, any construction operation (particularly a slope faceexcavation operation) can be performed very easily and with a highdegree of accuracy while constructing the controlling systems 1A' and 1Bin a simple construction, and the finish accuracy of a slope face can beaugmented remarkably.

Further, in the present embodiment, since the stick controlling system1B' feedback controls the stick cylinder 121 based on a calculationtarget stick position and posture information of the stick (the stickcylinder length) and the boom controlling system 1A' feedback controlsthe hydraulic cylinder 120 based on a composite target boom position andposture information of the boom (the boom cylinder length) so that theboom 200 may assume a predetermined posture, the controls describedabove can be realized with a simple construction, and this alsocontributes to reduction in cost of the present apparatus.

Further, since, in this instance, the posture information of the stick300 is detected from extension/contraction displacement information ofthe stick cylinder 121 and the posture information of the boom 200 isdetected from extension/contraction displacement information of the boomcylinder 120, the actual postures of the stick 300 and the boom 200 canbe detected simply and conveniently with certainty, and the accuracy ofthe posture detection of the boom 200 and the stick 300 can be augmentedwith a very simple construction.

Furthermore, since, in the actual boom control target value calculationsection 34 described above, the actual bucket tip position calculationsection 34A calculates the bucket tip position from the actual postureinformation of the boom 200 and the stick 300 and the actual target boomposition calculation section 34B determines the actual target boomposition from the bucket tip position obtained by the actual bucket tipposition calculation section 34A, the boom cylinder 120 can becontrolled so that the bucket tip position may assume a desired positionaccurately, and a slope face can be formed with a very high degree ofaccuracy upon slope face excavation or the like.

Further, since the composite target boom position calculation section 35adds a weight coefficient "W (0≦W≦1)" (refer to FIG. 27) to thecalculation target base position and adds another weight coefficient"1-W" to the actual target boom position to determine a composite targetboom position, to which one of the calculation target boom position andthe actual target boom position importance should be attached can bevaried simply and conveniently, and only by setting the one weightcoefficient "W", to which one of the calculation target boom positionand the actual target boom position importance should be attached can beset and composition processing of the target values can be performed ata very high speed.

Furthermore, since the weight coefficient "W" described above is set sothat it decreases as the extension amount of the stick cylinder 121increases (refer to FIG. 28), control wherein increasing importance isattached to the actual target boom position as the extension amount ofthe hydraulic cylinder 121 increase is performed. Consequently, forexample, an error from an ideal posture which arises from a high weightof the boom 200 as the extension amount of the stick cylinder 121increases can be suppressed efficiently and the boom 200 can becontrolled with a high degree of accuracy to a predetermined posture.

Further, in the present embodiment, while the hydraulic circuits for theboom cylinder 120 and the stick cylinder 121 are of the open center typeand the extension/contraction displacement velocities of the cylindertype actuators are varied in response to the loads acting upon thehydraulic cylinders, it is very effective to control the cylinder 120taking the actual postures of the boom 200 and the stick 300 intoconsideration as described above, and the construction operationaccuracy can be augmented remarkably.

It is to be noted that, while, in the present embodiment, the boom 200(hydraulic cylinder 120) of the boom 200 and the stick 300 as a pair ofarm members is controlled based on a composite target boom positiondetermined from an actual target boom position and a calculation targetboom position, it is possible to conversely determine a composite targetstick position from an actual target stick position and a calculationtarget stick position and control the stick 300 (hydraulic cylinder 121)based on the composite target stick position.

(6) Description of the Sixth Embodiment

In the following, a control apparatus for a construction machineaccording to a sixth embodiment is described principally with referenceto FIGS. 29 to 30. It is to be noted that the general construction of aconstruction machine to which the present sixth embodiment is applied issimilar to the contents described hereinabove with reference to FIG. 1and so forth in connection with the first embodiment described above,and the general construction of controlling systems of the constructionmachine is similar to the contents described hereinabove with referenceto FIGS. 2 to 4 in connection with the first embodiment described above.Further, the forms of representative semiautomatic modes of theconstruction machine are similar to the contents described hereinabovewith reference to FIGS. 9 to 14 in connection with the first embodimentdescribed above. Therefore, description of portions corresponding tothem is omitted, and in the following, description principally ofdifferences from the first embodiment is given.

By the way, in a common hydraulic excavator, for example, when anoperation (raking) of automatically moving the tip of the bucket 400linearly such as, for example, a horizontal leveling operation using acontroller, solenoid valves (control valve mechanisms) in hydrauliccircuits which effect supply and discharge of operating oil to and fromthe hydraulic cylinders 120, 121 and 122 electrically by PID feedbackcontrol to control extension/contraction operations of the hydrauliccylinders 120, 121 and 122 to control the postures of the boom 200,stick 300 and bucket 400.

In the hydraulic circuits which control the extension/contractionoperations of the hydraulic cylinders 120, 121 and 122, a hydraulic oilpressure is normally produced by a pump which is driven by an engine(prime mover). In this instance, if the rotational speed of the engineis varied by an external load or the like, then the rotational speed ofthe pump is varied by the variation of the rotational speed of theengine, and also the discharge (delivery capacity) of the pump isvaried. Consequently, even if the instruction values (electric currents)to the solenoid valves are same, the extension/contraction velocities ofthe hydraulic cylinders 120, 121 and 122 are varied. As a result, theposture control accuracy of the bucket 400 is deteriorated, and thefinish accuracy of a horizontal leveled face or the like by the bucket400 is deteriorated.

Therefore, it is a possible idea to use, in order to cope of such avariation of the rotational speed of the engine as described above, apump of the variable discharge type (variable delivery pressure type,variable capacity type) for the pumps and adjust the tilt angles of thepumps to control so that, even if the rotational speed of the engine(that is, the rotational speeds of the pumps) is varied, the deliverycapacity of the pumps may be fixed. However, since such tilt anglecontrol is low in responsibility, target cylinder extension/contractionvelocities cannot be secured, and deterioration of the finish accuracycannot be avoided.

Therefore, the control apparatus for a construction machine as the sixthembodiment of the present invention solves such a subject as describedabove and is constructed such that, even if a delivery capacityvariation factor of the pumps occurs with the engine (prime mover), theoperation velocities of cylinder type actuators can be secured quicklyagainst the variation to achieve augmentation of the finish accuracy.

First, a general construction of the control apparatus for aconstruction machine of the present embodiment is described. Asdescribed already with reference to FIG. 2, hydraulic circuits (fluidpressure circuits) for the hydraulic cylinder 120 to 122, the hydraulicmotor and the revolving motor are provided, and in the hydrauliccircuits, in addition to pumps 51 and 52 of the variable discharge type(variable delivery pressure type, variable capacity type) which aredriven by an engine 700 (prime mover of the rotational output type suchas a Diesel engine), a boom main control valve (control valve, controlvalve mechanism) 13, a stick main control valve (control valve, controlvalve mechanism) 14, a bucket main control valve (control valve, controlvalve mechanism) 15 and so forth are interposed. The pumps 51 and 52 ofthe variable discharge type can vary the discharges of operating oil tothe hydraulic circuits by individually adjusting the tilt angles thereofby means of an engine pump controller 27 which will be hereinafterdescribed. It is to be noted that, where a line which interconnectsdifferent components in FIG. 2 is a solid line, this indicates that theline is an electric circuit, but where a line which interconnectsdifferent components is a broken line, this indicates that the line is ahydraulic circuit.

The engine pump controller 27 receives engine rotational speedinformation from an engine rotational speed sensor 23 and controls thetilt angles of the engine 700 and the pumps 51 and 52 of the variabledischarge type (variable delivery pressure type, variable capacitytype), and can communicate coordination information with the controller1.

In the control apparatus of the present embodiment, control sections 1Ato 1C of the controller 1 shown in FIG. 29 serve as controlling meansfor supplying control signals (solenoid valve instruction valves) tosolenoid proportional valves 3A to 3C based on detection resultsdetected by the resolvers 20 to 22 (actually the results afterconversion by the signal converter 26) so that the boom 200, stick 300and bucket 400 may have predetermined postures to control the cylinders120 to 122, respectively. Further, in the present embodiment, the primemover for driving the pumps 51 and 52 is the engine (Diesel engine) 700of the rotational output type, and the engine rotational speed sensor 23functions as variation factor detection means for detecting therotational speed of the engine 700 as a delivery capacity variationfactor of the pumps 51 and 52.

Then, as shown in FIG. 29, correction circuits (correction means) 60A,60B and 60C are provided in the stage following the control sections 1A,1B and 1C in the controller 1, respectively. The correction circuits(correction means) 60A to 60C correct, if a delivery capacity variationfactor of the pumps 51 and 52 is detected by the engine rotational speedsensor 23, then solenoid valve instruction values from the controlsections 1A to 1C in response to the delivery capacity variation factor.More particularly, the correction circuits 60A to 60C correct solenoidvalve instruction values from the control sections 1A to 1C in responseto a detection result of the engine rotational speed sensor 23 andoutputs modified solenoid valve instruction values obtained by thecorrection to the solenoid proportional valves 3A to 3C. A detailedconstruction of the correction circuits 60A to 60C is shown in FIG. 30.

As shown in FIG. 30, each of the correction circuits 60A to 60C includesa subtractor 60a, an engine rotation compensation table 60b and amultiplier 60c.

The subtractor (deviation calculation means) 60a calculates a deviationbetween an engine rotational speed set value (reference rotational speedinformation) and an actual engine rotational speed (actual rotationalspeed information) of the engine 700 detected by the engine rotationalspeed sensor 23, [engine rotational speed set value]-[actual enginerotational speed].

Here, the engine rotational speed set value is set by operator operatinga throttle dial (not shown), and information corresponding to theposition of the throttle dial is set as an engine rotational speed setvalue into a predetermined area on a memory (for example, a RAM) or aregister which composes the controller 1. In short, in the presentembodiment, the throttle dial not shown and the predetermined area onthe memory or the register function as reference rotational speedsetting means for setting reference rotational speed information of theengine 700.

Meanwhile, the engine rotational speed compensation table 60b and themultiplier 60c function as correction information calculation means forcalculating correction information for correcting a solenoid valveinstruction value (control signal) in response to a deviation obtainedby the subtractor 60a.

The engine rotational speed compensation table 60b is provided to outputa correction coefficient (correction information) for correcting asolenoid valve instruction value corresponding to a deviation from thesubtractor 60a and is stored in advance in a memory (for example, a ROMor a RAM) which composes the controller 1 such that, by using a tablelookup technique, a correction coefficient corresponding to a deviationfrom the subtractor 60a is read out.

The multiplier 60c multiplies a solenoid valve instruction value fromeach of the control section 1A to 1C and a correction coefficient readout from the engine rotational speed compensation table 60b and outputsthe product as a modified solenoid valve instruction value to each ofthe solenoid proportional valves 3A to 3C.

In the engine rotational speed compensation table 60b, correctioncoefficients linear with respect to the engine rotational speeddeviation calculated by the subtractor 60a are set, for example, asillustrated in FIG. 30.

Particularly, where the engine rotational speed set value and the actualengine rotational speed are equal (where the deviation is 0), 1 is setas the correction coefficient, and from the multiplier 60c, solenoidvalve instruction values from the control sections 1A to 1C areoutputted as they are without being varied, but when the actual enginerotational speed drops (when the deviation becomes a positive value),since the discharges of the pumps 51 and 52 are reduced, correctioncoefficients higher than 1 are set so that the instruction values(electric currents) to the solenoid proportional valves 3A to 3C may beincreased by the reduced amounts, and the solenoid valve instructionvalues from the control sections 1A to 1C are outputted from themultiplier 60c after they are varied by great amounts with thecorrection coefficients.

On the contrary, when the actual engine rotational speed increases (whenthe deviation becomes a negative value), since the discharges of thepumps 51 and 52 increase, correction coefficients smaller than 1 are setso that the instruction values (electric currents) to the solenoidproportional valves 3A to 3C may be decreased by the increased amounts,and the solenoid valve instruction values from the control sections 1Ato 1C are outputted from the multiplier 60c after they are varied bysmall amounts with the correction coefficients.

It is to be noted that the correction coefficients of the enginerotational speed compensation table 60b may be set linearly over theoverall range of the engine rotational speed deviation or an upper limitvalue and a lower limit value may be provided.

Since the control apparatus for a construction machine as the sixthembodiment of the present invention is constructed in such a manner asdescribed above, if a delivery capacity variation factor of the pumps 51and 52 by the engine 700 (a variation of the rotational speed of theengine 700) is detected by the engine rotational speed sensor 23, thenthe instruction values from the control sections 1A to 1C to thesolenoid proportional valves 3A to 3C are corrected in response to thevariation, and consequently, even if a delivery capacity variationfactor of the pumps 51 and 52 occurs, control of the solenoidproportional valves 3A to 3C and hence the main control valves 13 to 15in accordance with the variation is performed, and the operationvelocities of the cylinders 120 to 122 can be secured rapidly inresponse to the variation.

Describing more particularly, if the rotational speed of the engine 700drops, then the solenoid valve instruction values from the controlsection 1A to 1C are multiplied by a correction coefficient larger than1 corresponding to the rotational speed deviations by the correctioncircuits 60A to 60C so that they are modified so as to become higherthan the initial values, and the modified solenoid valve instructionvalues are supplied to the solenoid proportional valves 3A to 3C.Accordingly, control of the solenoid proportional valves 3A to 3C (maincontrol valves 13 to 15) corresponding to the reduced amounts of thedischarges of the pumps 51 and 52 caused by the drop of the rotationalspeed of the engine 700 is performed, and the operation speeds of thecylinders 120 to 122 is secured.

On the contrary, if the rotational speed of the engine 700 increases,then the solenoid valve instruction values from the control sections 1Ato 1C are multiplied by a correction coefficient smaller than 1 inaccordance with the rotational speed deviations by the correctioncircuits 60A to 60C so that they are modified so as to become lower thanthe initial values, and the modified solenoid valve instruction valuesare supplied to the solenoid proportional valves 3A to 3C. Accordingly,control of the solenoid proportional valves 3A to 3C (main controlvalves 13 to 15) corresponding to the increased amounts of thedischarges of the pumps 51 and 52 caused by the drop of the rotationalspeed of the engine 700 is performed, and the operation speeds of thecylinders 120 to 122 are secured.

Prevention of control accuracy deterioration by the engine rotationalspeed sensor 23 is such as follows. In particular, with regard tocorrection of a target bucket tip velocity, the target bucket tipvelocity is determined by the positions of the operation levers 6 and 8and the engine rotational speed. Further, since the hydraulic pumps 51and 52 are directly coupled to the engine 700, when the enginerotational speed is low, also the pump discharges decrease and thecylinder velocities decrease. Therefore, the engine rotational speed isdetected, and the target bucket tip velocity is calculated so that itmay match with the variations of the pump discharges. Such an operationas just described is performed, in the present embodiment, in parallelto operations by the correction circuits 60A to 60C described above.

While various controls are performed by the controller 1 in this manner,in the system according to the present embodiment, if a rotational speedvariation of the engine 700 is detected by the engine rotational speedsensor 23, then control signals (instruction values) to the solenoidproportional valves 3A to 3C are corrected in response to the rotationalspeed variation amount (deviation between the actual engine rotationalspeed and the engine rotational speed set value), even if a deliverycapacity variation factor of the pumps 51 and 52, for example, avariation of the rotational speed of the engine 700, occurs, hydrauliccircuit control (control of the solenoid proportional valves 3A to 3Cand the main control valves 13 to 15) corresponding to the variation isperformed. Accordingly, the cylinders 120 to 122 are controlled rapidlyagainst the variation and the operation velocities thereof are secured,and the finish accuracy of a horizontally leveled face by the bucket 400is augmented significantly.

Further, in the present embodiment, by adjusting the tilt angles of thepumps 51 and 52 in response to a detection result by the enginerotational speed sensor 23 by means of the engine pump controller 27,tilt angle control for controlling the delivery capacities of the pumps51 and 52 so that they may be fixed even if the rotational speed of theengine 700 varies is performed in parallel, and by using both of thistilt angle control and the correction operation of the solenoid valveinstruction values by the correction circuits 60A to 60C, acountermeasure against a delivery capacity variation factor of the pumps51 and 52 can be taken further rapidly, which contributes toaugmentation of the finish accuracy.

(7) Description of the Seventh Embodiment

In the following, a control apparatus for a construction machineaccording to a seventh embodiment is described principally withreference to FIGS. 31 to 33. It is to be noted that the generalconstruction of a construction machine to which the present seventhembodiment is applied is similar to the contents described hereinabovewith reference to FIG. 1 and so forth in connection with the firstembodiment described above, and the general construction of controllingsystems of the construction machine is similar to the contents describedhereinabove with reference to FIGS. 2 to 4 in connection with the firstembodiment described above. Further, the forms of representativesemiautomatic modes of the construction machine are similar to thecontents described hereinabove with reference to FIGS. 9 to 14 inconnection with the first embodiment described above. Therefore,description of portions corresponding to them is omitted, and in thefollowing, description principally of differences from the firstembodiment is given.

Generally, the hydraulic excavator is constructed such that the boom 200(hydraulic cylinder 120), stick 300 (hydraulic cylinder 121) and bucket400 (hydraulic cylinder 122) are electrically PID feedback controlledindividually using solenoid valves or the like, and can keep a desiredtarget operation (posture) accurately while suitably correcting controlof the position and the posture of the working member.

It is to be noted that it is assumed here that, for hydraulic circuitsfor at least the boom 200 (hydraulic cylinder 120) and the stick 300(hydraulic cylinder 121), a so-called open center type circuit whereinthe extension/contraction displacement velocities of the hydrauliccylinders 120 and 121 vary depending upon the loads applied to thehydraulic cylinders 120 and 121, respectively, is used.

By the way, in the hydraulic excavator described above, since an opencenter type circuit is used for the hydraulic circuits as describedabove, for example, where the excavation load is very heavy, as the loadincreases, the hydraulic pressures of the boom 200 (hydraulic cylinder120) and the stick 300 (hydraulic cylinder 121) rise and theextension/contraction displacement velocities of the hydraulic cylinders120 and 121 decrease, and the operations of the boom 200 and the stick300 (that is, the operation of the bucket tip) are sometimes stoppedfinally.

In this instance, in a PID feedback controlling system, since thevelocity information (P) of the bucket tip is reduced to zero and theposition information (D) is fixed to a value equal to that upon stoppingof the stick, the information (proportional operation factors) does nothave an influence on target velocities for the extension/contractiondisplacement velocities of the hydraulic cylinders 120 and 121, butsince I (integration factor) is involved in the controlling system, thetarget velocities of the hydraulic cylinders 120 and 121 continue toincrease resultantly.

Accordingly, if, for example, a rock under excavation which has beencaught by the bucket tip breaks in this condition and the load isremoved suddenly from the boom 200 and the stick 300, then the hydrauliccylinders 121 and 122 will suddenly begin to move at velocities muchhigher than their target velocities. As a result, the finish accuracy inan excavation operation is deteriorated significantly.

Therefore, the control apparatus for a construction machine as theseventh embodiment of the present invention is constructed such that theextension/contraction displacement velocities of the cylinders 121 and122 are reduced in response to an increase of the loads to the hydrauliccylinders 121 and 122 so that, even if the loads acting upon thehydraulic cylinders 121 and 122 are removed suddenly, theextension/contraction displacements of the cylinders 121 and 122 can becontrolled smoothly.

First, a general construction of the present apparatus is described. Thecontroller 1 of the present apparatus includes control section 1A, 1Band 1C for the cylinders 120, 121 and 122, and each of the controls isformed as a control feedback loop (refer to FIGS. 3 and 4).

The compensation construction in the closed loop controls shown in FIG.4 has, in each of the boom control sections 1A, 1B and 1C, a multiplefreedom degree construction of a feedback loop and a feedforward loopwith regard to the displacement and the velocity as shown in FIG. 5, andincludes feedback loop type compensation means 72 having a variablecontrol gain (control parameter), and feedforward type compensationmeans 73 having a variable control gain (control parameter).

In particular, if a target velocity (control target value) is given fromoperation position information of the operation levers (arm mechanismoperation members) 6 and 8 by a target cylinder velocity setting section(control target value setting means) 80, then as regards feedback loopprocessing, feedback loop processes according to a route wherein adeviation between the target velocity and velocity feedback informationis multiplied by a predetermined gain Kvp (refer to reference numeral62), another route wherein the target velocity is integrated once (referto an integration element 61 of FIG. 5) and a deviation between thetarget velocity integration information and displacement feedbackinformation is multiplied by a predetermined gain Kpp (refer toreference numeral 63) and a further route wherein the deviation betweenthe target velocity integration information and the displacementfeedback information is multiplied by a predetermined gain Kpi (refer toreference numeral 64) and further integrated (refer to reference numeral66) are performed while, as regards the feedforward loop processing, afeedforward loop process by a route wherein the target velocity ismultiplied by a predetermined gain Kf (refer to reference numeral 65) isperformed.

In short, in the control sections 1A, 1B and 1C of the presentembodiment, the hydraulic cylinders 120, 121 and 122 are controlled,respectively, by the feedback controlling systems each of which has atleast a proportional operation factor and an integration operationfactor so that the boom 200 and the stick 300 may assume predeterminedpostures (in the present embodiment, particularly so that the bucket 400may move at a predetermined moving velocity).

It is to be noted that the values of the gains Kvp, Kpp, Kpi and Kfmentioned above can individually be varied by a gain scheduler (controlparameter scheduler) 70, and the boom 200, the bucket 400 and so forthare controlled to target operation conditions by varying and correctingthe values of the gains Kvp, Kpp, Kpi and Kf in this manner.

Further, while a non-linearity removal table 71 is provided as shown inFIG. 5 to remove non-linear properties of the solenoid proportionalvalves 3A to 3C, the main control valves 13 to 15 and so forth, aprocess in which the non-linearity removal table 71 is used is performedat a high speed by a computer using a table lookup technique.

In the following, a construction of essential part of the presentembodiment is described. Of the control sections 1A, 1B and 1C, thecontrol section 1B includes, as shown in FIG. 31, a cylinder loaddetection section (actuator load detection means) 181, switches 182 and183, a low-pass filter 184, a differentiation processing section 185, aswitch control section 186 and a target cylinder velocity correctionsection 187, and an I gain correction section 70a is provided in thegain scheduler 70.

Here, the cylinder load detection section 181 detects a load conditionto the hydraulic cylinder 121, and the switches 182 and 183 effectswitching between a route 188 along which load information of thehydraulic cylinder 121 detected by the cylinder load detection section181 is outputted as it is to the target cylinder velocity correctionsection 187 and another route 189 along which the load information isoutputted to the target cylinder velocity correction section 187 afteran integration process is performed for it by the low-pass filter 184,and are switched simultaneously by the switch control section 186.

The target cylinder velocity correction section (first or fourthcorrection means) 187 reduces, when the cylinder load detected by thecylinder load detection section 181 is higher than a predeterminedvalue, a target velocity set by the target cylinder velocity settingsection 80 in response to the cylinder load condition then to reduce themoving velocity of the bucket 400 by the hydraulic cylinder 121, and isconstructed such that it multiplies load information inputted theretothrough the route 188 or 189 by a target bucket velocity coefficienthaving such a characteristic as illustrated, for example, in FIG. 32 toincrease the reduction amount of the target velocity as the cylinderload increases to decrease the moving velocity of the bucket 400.

Consequently, even if the load to the cylinder 121 is removed suddenly,the control section 1B can control smoothly without varying theextension/contraction displacement of the cylinder 121 (the movingvelocity of the bucket 400) suddenly.

By the way, the low-pass filter (integration means) 184 described abovehas, in the present embodiment, such an integration characteristic asillustrated in this FIG. 31, and is provided to integrate, when loadinformation of the hydraulic cylinder 121 detected by the cylinder loaddetection section 181 is inputted, the load information to moderate thevariation of the load information with respect to the time axis so that,if the switches 182 and 183 are switched to the present low-pass filter184 (route 189) side, then the variation of input load information tothe target cylinder velocity correction section 187 may be moderated. Itis to be noted that an integrating circuit other than a low-pass filtermay be used for this integration means.

Further, the differentiation processing section 185 performsdifferentiation processing for load information detected by the cylinderload detection section 181 to detect the rate of change of the loadinformation with respect to time. The switch control section 186switches the switches 182 and 183 in response to the rate of change ofthe load information obtained by the differentiation processing section185. Here, the switch control section 186 switches the switches 182 and183 to the route 188 side when the rate of change of the loadinformation is positive, but switches the switches 182 and 183 to theroute 189 side when the rate of change of the load information isnegative.

In short, in the present control section 1B, in a transient conditionwherein the rate of change of the load information is negative (when theload acting upon the hydraulic cylinder 121 decreases) and the cylinderload detected by the cylinder load detection section 181 changes from acondition wherein it is higher than a predetermined value to anothercondition wherein it is lower than the predetermined value, the switches182 and 183 are switched to the low-pass filter 184 side so that themoving velocity of the bucket 400 by the hydraulic cylinder 121 isincreased based on the load information obtained through the low-passfilter 184.

Consequently, since the control section 1B increases, when the loadacting upon the cylinder 121 decreases, the moving velocity of thebucket 400 based on load information whose variation is moderated by thelow-pass filter 184, even if the load acting upon the bucket 400 isremoved suddenly, the bucket 400 can be moved slowly and smoothly.

It is to be noted that, in the present embodiment, this function (thirdor sixth correction means) is realized by the low-pass filter 184 andthe target cylinder velocity correction section 187.

Meanwhile, the I gain correction section (second or fifth correctionmeans) 70a provided in the gain scheduler 70 regulates, when cylinderload information detected by the cylinder load detection section 181 ishigher than the predetermined value, the feedback control by the I gainKpi, which is an integration operation factor, in response to thecylinder load condition. Here, the I gain correction section 70amultiplies the I gain Kpi by an I gain coefficient having such acharacteristic as illustrated, for example, in FIG. 33 to increase theregulation amount of the feedback control by the I gain Kpi in responseto the increase of the cylinder load so that the I gain Kpi may approachzero.

In short, the present I gain correction section 70a prevents theextension/contraction displacement velocity of the cylinder 121 fromcontinuing to be increased by an integration operation factor even ifthe load to the cylinder 121 becomes extremely high and exceeds thepredetermined value. It is to be noted that, in this instance, since nosuch regulation is performed for the other gains Kf, Kpp and Kvp(proportional operation elements), a minimum necessary excavation force(extension/contraction displacement velocity of the hydraulic cylinder121) upon excavation by the bucket 400 is secured (maintained) by thegains Kf, Kpp and Kvp.

It is to be noted that, while, in the present embodiment, only thecontrol section 1B has the construction shown in FIG. 31, also thecontrol section 1A which is a boom controlling system may be constructedin a similar manner as that shown in FIG. 31.

Since the control apparatus for a construction machine as the seventhembodiment of the present invention is constructed in such a manner asdescribed above, upon semiautomatic control, if the cylinder loaddetected by the cylinder load detection section 181 in the controlsection 1B is higher than the predetermined value, then the reductionamount of the target velocity is increased as the cylinder loadincreases to decrease the moving velocity of the bucket 400 while theregulation amount of the feedback control by the I gain Kpi is increasedso that the I gain Kpi may approach zero.

Consequently, even if a rock under excavation which has been caught bythe tip 112 breaks or the like and the load to the hydraulic cylinder121 is removed suddenly, the bucket 400 is controlled smoothly without asudden variation of the moving velocity thereof. Meanwhile, when theload acting upon the hydraulic cylinder 121 decreases, since the movingvelocity of the bucket 400 is increased based on load information whosevariation is moderated by the low-pass filter 184, even if the loadacting upon the bucket 400 is removed suddenly as described above, thebucket 400 operates slowly and smoothly.

Therefore, in the system according to the present embodiment, since thecontrol section 1B controls the stick cylinder 121 such that, when theload to the stick cylinder 121 is higher than the predetermined value,the target velocity is reduced to reduce the extension/contractiondisplacement velocity of the stick cylinder 121, even if the load to thecylinder 121 is removed suddenly, the bucket 400 can be controlled verysmoothly without allowing the extension/contraction displacement of thecylinder 121 to vary suddenly. Accordingly, the finish accuracy in adesired construction operation such as formation of a slope face isaugmented significantly.

Further, in this instance, since the control section 1B feedbackcontrols the cylinder 121 based on a target velocity and postureinformation of the stick 300 so that the bucket 400 may move at apredetermined moving velocity, the moving velocity of the bucket 400 canbe controlled further accurately, and the finish accuracy in a desiredconstruction operation is further augmented.

Here, since the posture information of the stick 300 described above isdetected, in the present embodiment, from extension/contractiondisplacement information of the cylinder 121, it can be acquired simplyand conveniently with a very simple construction, and this contributesvery much to simplification of the controller 1.

Further, since, where the load to the cylinder 121 is higher than thepredetermined value, the feedback control of the cylinder 121 by the Igain Kpi is regulated in response to the load condition, it can beprevented with certainty that the extension/contraction displacementvelocity of the cylinder 121 (the excavation force of the bucket 400)continues to be increased by an integration operation factor while aminimum necessary extension/contraction displacement velocity of thehydraulic cylinder 121 is secured (maintained). Accordingly, a desiredconstruction operation can be performed with a high degree of accuracyand efficiently.

Further, in the present embodiment, since, as the load to the cylinder121 increases, the reduction amount of the target velocity is increased(refer to FIG. 32) to reduce the moving speed of the bucket 400, themoving speed of the bucket 400 can be reduced (varied) very smoothlywith simple and easy setting, and this contributes very much tosimplification of the controller 1 and augmentation of the performance.

Further, in the present embodiment, since the regulation amount of thefeedback control by the I gain Kpi is increased as the load to thecylinder 121 increases as described with reference to FIG. 33, anincrease of the extension/contraction displacement velocity of thecylinder 121 (the moving speed of the bucket 400) by the I gain Kpi canbe prevented to cope with a sudden load variation to the cylinder 121very rapidly with simple and easy setting.

Furthermore, since, in a transition condition wherein the load to thecylinder 121 comes to a condition wherein it is lower than thepredetermined value, the moving speed of the bucket 400 is increasedbased on the load information whose variation is moderated by thelow-pass filter 184, even if the load to the cylinder 121 is removedsuddenly, the moving speed of the bucket 400 can be increased slowly.Accordingly, even if the load is removed suddenly, the bucket 400 iscontrolled very smoothly, and consequently, the finish accuracy in adesired construction operation is further augmented significantly.

It is to be noted that, wile the control section 1B described above iseffective particularly where the hydraulic circuit for the cylinder 121is of the open center type, similar actions and effects to thosedescribed above can be anticipated even where it is applied to ahydraulic circuit of another type.

Further, while, in the present embodiment, the I gain correction section70a, low-pass filter 184 and target cylinder velocity correction section187 are provided in the control section 1B, a countermeasure against asudden load variation to the cylinder 121 can be taken if at least thetarget cylinder velocity correction section 187 is provided.

(8) Description of the Eighth Embodiment

In the following, a control apparatus for a construction machineaccording to an eighth embodiment is described principally withreference to FIGS. 34 to 36. It is to be noted that the generalconstruction of a construction machine to which the present eighthembodiment is applied is similar to the contents described hereinabovewith reference to FIG. 1 and so forth in connection with the firstembodiment described above, and the general construction of controllingsystems of the construction machine is similar to the contents describedhereinabove with reference to FIGS. 2 to 4 in connection with the firstembodiment described above. Further, the forms of representativesemiautomatic modes of the construction machine are similar to thecontents described hereinabove with reference to FIGS. 9 to 14 inconnection with the first embodiment described above. Therefore,description of portions corresponding to them is omitted, and in thefollowing, description principally of differences from the firstembodiment is given.

By the way, in a common hydraulic excavator, such control that the angle(bucket angle) of the bucket 400 with respect to a horizontal direction(vertical direction) is always kept fixed even if the boom 200 and thestick 300 are moved such as where excavated sand and earth or the likeare conveyed while they are accommodated in the bucket 400 is sometimesrequired.

In this instance, with the PID feedback controlling system for thebucket 400 (hydraulic cylinder 122), if the deviation between the actualbucket angle and the target bucket angle becomes large during operationof the boom 200 and the stick 300, then the instruction value (controltarget value) to the hydraulic cylinder 122 is increased to decrease thedeviation by an action of the I (integration factor) of the P(proportion factor), I (integration factor) and D (differentiationfactor).

However, when the operation levers (operation members) 6 and 8 for theboom 200, stick 300 and bucket 400 are moved to their neutral positions(inoperative positions) to stop the bucket 400, in the controllingsystem described above, since the instruction value to the hydrauliccylinder 122 is not reduced to zero immediately due to an accumulationamount of the I (integration factor) till the stopping time, even if theoperation levers 6 and 8 are moved to the inoperative positions, thebucket 400 does not stop immediately and an overshoot occurs, resultingin deterioration of the control accuracy.

The control apparatus for a construction machine as the eighthembodiment of the present invention is constructed so as to solve such asubject as just described, and prevents an overshoot of the bucket(working member) 400 when the operation levers 6 and 8 are positioned totheir inoperative positions thereby to achieve augmentation of thecontrol accuracy of the working member.

In the following, the present embodiment is described. First, in thepresent embodiment, boom hydraulic cylinder extension/contractiondisplacement detection means for detecting extension/contractiondisplacement information of the boom hydraulic cylinder 120 is composedof the signal converter 26 and the resolver 20 which serves as boomposture detection means, and stick hydraulic cylinderextension/contraction displacement detection means for detectingextension/contraction displacement information of the stick hydrauliccylinder 121 is composed of the signal converter 26 and the resolver 21which serves as stick posture detection means, and furthermore, buckethydraulic cylinder extension/contraction displacement detection means iscomposed of the signal converter 26 and the resolver 22 which serves asbucket posture detection means (refer to FIG. 1)

The boom control sections 1A, 1B and 1C of the controller 1 basicallyhave a multiple freedom degree construction of a feedback loop and afeedforward loop with regard to the displacement and the velocity andincludes feedback loop type compensation means 72 having a variablecontrol gain (control parameter), feedforward type compensation means 73having a variable control gain (control parameter), and target cylindervelocity setting means 80 for determining target velocities (controltarget values) of the cylinders 120, 121 and 122 from operation positioninformation of the operation levers 6 and 8 (refer to FIG. 5).

In particular, if a target velocity (control target value) is given fromoperation position information of the operation levers (arm mechanismoperation members) 6 and 8 by the target cylinder velocity settingsection (control target value setting means) 80, then as regardsfeedback loop processing, feedback loop processes according to a route(differentiation operation factor D) wherein a deviation between thetarget velocity and velocity feedback information is multiplied by apredetermined gain Kvp (refer to reference numeral 62), another route(proportion operation factor P) wherein the target velocity isintegrated once (refer to an integration element 61 of FIG. 5) and adeviation between the target velocity integration information anddisplacement feedback information is multiplied by a predetermined gainKpp (refer to reference numeral 63) and a further route (integrationoperation factor I) wherein the deviation between the target velocityintegration information and the displacement feedback information ismultiplied by a predetermined gain Kpi (refer to reference numeral 64)and further integrated (refer to reference numeral 66) are performedwhile, as regards the feedforward loop processing, a process by a routewherein the target velocity is multiplied by a predetermined gain Kf(refer to reference numeral 65) is performed.

In short, in the control sections 1A, 1B and 1C of the presentembodiment, the hydraulic cylinders 120, 121 and 122 are controlled,respectively, by the PID feedback controlling systems each of which hasthe proportional operation factor P, the integration operation factor Iand the differentiation operation factor D, based on the given targetvelocity and posture information of the boom 200, stick 300 and bucket400 detected by the resolvers 20 to 22 (here, extension/contractiondisplacement information of the cylinders 120, 121 and 122 detected bythe respective resolvers 20, 21 and 22) so that the boom 200 and thestick 300 may assume predetermined postures.

It is to be noted that the values of the gains Kvp, Kpp, Kpi and Kfmentioned above can individually be varied by a gain scheduler (controlparameter scheduler) 70, and the boom 200, the bucket 400 and so forthare controlled to target operation conditions by varying and correctingthe values of the gains Kvp, Kpp, Kpi and Kf in this manner.

Further, while a non-linearity removal table 71 is provided in order toremove non-linear properties of the solenoid proportional valves 3A to3C, the main control valves 13 to 15 and so forth, a process in whichthe non-linearity removal table 71 is used is performed at a high speedby a computer using a table lookup technique.

However, in the present embodiment, in order to prevent an overshoot ofthe bucket 400 particularly in the bucket angle control mode, thecontrol section 1C which is a bucket controlling system is constructedsuch that, as shown in FIGS. 34 and 35, the target cylinder velocitysetting section 80 is formed as target bucket cylinder lengthcalculation means 80' and the control section 1C includes controldeviation detection means 281, an AND gate (logical AND circuit) 282 anda switch 283. It is to be noted that reference symbols in FIGS. 34 and35 same as those shown in FIG. 5 are similar to those describedhereinabove with reference to FIG. 5.

Here, the target bucket cylinder length calculation means 80' determinesa target length (control target value) of the bucket cylinder 122 bypredetermined calculation from an actual boom angle θbm' (refer to FIG.36) and an actual stick angle θst' (refer to FIG. 36), and in thepresent control section 1C, PID feedback control is performed based on avalue (velocity information) obtained by differentiation of a controltarget value obtained by the calculation means 80' by differentiation.

In particular, in the present target bucket cylinder length calculationmeans 80', a target bucket cylinder length is calculated usingcalculation expressions (3-1) to (3-7) given below. It is to be notedthat, in the following description, L_(i/j) represents a fixed length,R_(i/j) a variable length, A_(i/j/k) a fixed angle, and θ_(i/j/k)represents a variable angle, the suffix i/j to L represents the lengthbetween nodes i and j, the suffix i/j/k to A and θ represents to connectthe nodes i, j and k in order of i→j→k. Accordingly, for example,L_(101/102) represents the distance between the node 101 and the node102, and θ_(103/104/105) represents the angle defined when the nodes 103to 105 are connected in order of the node 103→node 104→node 105.

Further, here, the node 101 is assumed to be the origin of the xycoordinate system as shown in FIG. 36, and the angle (boom angle)defined by a straight line interconnecting the origin and the node 104and the x axis is represented by θbm', the angle (stick angle) definedby the straight line interconnecting the origin and the node 104 andanother straight line interconnecting the nodes 104 and 107 isrepresented by θst', and the angle defined by the straight lineinterconnecting the nodes 104 and 107 and the bucket 400 is representedby θbk'. However, the angles shown in FIG. 36 are represented aspositive angles when taken in the counterclockwise direction, andtherefore, both of the angles θst' and θbk' assume negative values.

First, the target bucket cylinder length (R_(106/109)) is represented inthe following manner in accordance with the cosine theorem:

    R.sub.106/109 =(L.sub.106/107.sup.2 +L.sub.107/109.sup.2 -2L.sub.106/107 ·L.sub.107/109 ·cos 2π-A.sub.104/107/106 -A.sub.104/107/108 -θ.sub.109/107/108).sup.1/2      (3-1)

Here, θ_(109/107/108) in the present expression (3-1) is represented as

    θ.sub.109/107/108 =θ.sub.109/107/110 +θ.sub.108/107/110 ( 3-2)

Further, θ_(109/107/110) and θ_(108/107/110) in the present expression(3-2) can be represented, in accordance with the cosine theorem, as

    θ.sub.109/107/108 =cos.sup.-1 [(L.sub.107/109.sup.2 +R.sub.107/110.sup.2 -L.sub.109/110.sup.2)/2L.sub.107/109 ·R.sub.107/110 ]                                 (3-3)

    θ.sub.108/107/110 =cos.sup.-1 [(L.sub.107/108.sup.2 +R.sub.107/110.sup.2 -L.sub.108/110.sup.2)/2L.sub.107/108 ·R.sub.107/110 ]                                 (3-4)

Here, since L_(107/108), L_(107/109), L_(108/110), and L_(109/110) inthe expressions (3-3) and (3-4) are all known fixed values, the targetbucket cylinder length R_(106/109) can be determined by determiningR_(107/110), substituting the expressions (3-3) and (3-4) into theexpression (3-2) and further substituting the expression (3-2) into theexpression (3-1). R_(107/110) can be represented, in accordance with thecosine theorem, as

    R.sub.107/110 =(L.sub.107/108.sup.2 +L.sub.108/110.sup.2 -2L.sub.107/108 ·L.sub.108/110 ·cos θ.sub.107/108/110).sup.1/2(3-5)

Further, θ_(107/108/110) in the present expression (3-5) can berepresented as

    θ.sub.107/108/110 =π-A.sub.104/108/107 -A.sub.110/108/115 -θbk'                                               (3-6)

Then, θbk' in the present expression (3-6) can be represented as afunction of the bucket angle φ (control target value), the actual boomangle θbm' and the stick angle θst' in the following manner.

    θbk'=φ-π-θbm'-θst'                (3-7)

Accordingly, if the actual boom angle θbm' and stick angle θst' areobtained by the resolvers 20 and 21, then R_(107/110) given above can bedetermined by substituting the expression (3-7) given above into theexpression (3-6) and then substituting the expression (3-6) into theexpression (3-5), and R_(107/110) given above can be determined bysubstituting the expression (3-6) given above into the expression (3-5),and finally, the target bucket cylinder length R_(106/109) can bedetermined in accordance with the expressions (3-1) through (3-4).

It is to be noted that, while here the target bucket cylinder lengthR_(106/109) is determined from the actual boom angle θbm' and stickangle θst' as described above, the target bucket cylinder lengthR_(106/109) may be determined from, for example, the length of the boomcylinder 120 and the length of the stick cylinder 121.

Then, referring to FIGS. 34 and 35, the control deviation detectionmeans 281 detects whether or not the control deviation of the feedbackcontrolling system is higher than a predetermined value, and the ANDgate 282 logically ANDs an output of the control deviation detectionmeans 281 and a signal when all of the operation levers 6 and 8 are attheir neutral positions (inoperative positions) so that it outputs an Hpulse when all of the operation levers 6 and 8 are at their neutralpositions and the control deviation described above is higher than thepredetermined value (this is determined as a first condition).

Then, the switch 283 exhibits an ON state when an H pulse is outputtedfrom the AND gate 282 described above, and when the switch 283 is in anON state, the feedback control route of the gain Kpi describedhereinabove is added to the feedback control route of the gain Kvp andthe feedback route of the gain Kpp described hereinabove.

In short, the present control section 1C includes a first controllingsystem (first control means) for performing PID feedback control by theroutes (proportion operation factor P, differentiation operation factorD and integration operation factor I) of the gain Kpp, the gain Kvp andthe gain Kpi when the first condition described above is satisfied, anda second controlling system (second control means) for performing PDfeedback control while feedback control by the route of Kpi (integrationoperation factor I) is inhibited when the first condition describedabove is not satisfied.

Since the control apparatus for a construction machine as the eighthembodiment of the present invention is constructed in such a manner asdescribed above, upon semiautomatic control, the moving velocity anddirection of the bucket tip 112 are first determined from information ofa target slope face set angle, pilot hydraulic pressures which controlthe stick cylinder 121 and the boom cylinder 120, a vehicle inclinationangle and an engine rotational speed, and target velocities of thecylinders 120, 121 and 122 are calculated based on the information. Itis to be noted that the information of the engine rotational speed inthis instance is required to determine an upper limit to the cylindervelocities.

In this instance, in the present embodiment, when all of the operationlevers 6 and 8 are at their neutral positions and the first conditionthat the control deviation described above is higher than thepredetermined value is satisfied, the switch 83 in the control section1C is put into an ON state and PID feedback control (feedback control bythe first control system described above) is performed, but when thefirst condition is not satisfied, the switch 83 exhibits an OFF stateand feedback control by the integration operation factor is inhibitedwhile PD feedback control (feedback control by the second control systemdescribed above) is performed.

Consequently, since feedback control by the integration operation factoris inhibited while the operation levers 6 and 8 are in their operativepositions (in short, while the bucket angle φ varies), for example, whenthe control deviation of the bucket cylinder 122 from its targetvelocity becomes large, such a large variation of the target velocitythat the target velocity of the bucket cylinder 122 becomes large by theintegration operation factor in order to decrease the control deviationcan be suppressed.

Accordingly, when the operation levers 6 and 8 are moved to theirneutral positions form a condition wherein they are in operativepositions (when the bucket angle φ is to be kept at a desired angle),where there is a control deviation (when the control deviation is largerthan the predetermined value), the switch 283 is switched ON to addfeedback control by the integration operation factor I to PD feedbackcontrol to effect PID feedback control as described above. Consequently,the control deviation which has not successfully been reduced fully tozero by PD feedback control can be reduced quickly toward zero tocontrol the extension/contraction displacement of the bucket cylinder122 (in short, the posture of the bucket 400) to a desired target value(bucket angle) rapidly and stop the bucket cylinder 122.

As described above, in the system according to the present embodiment,when the operation levers 6 and 8 are in their neutral positions (whenthe bucket 400 is to be stopped) and the control deviation is higherthan the predetermined value, the control section 1C adds feedbackcontrol by the integration operation factor I to PD feedback control toeffect PID feedback control, the control deviation which has notsuccessfully been reduced fully to zero only by PD feedback control canbe reduced toward zero very rapidly to control the bucket 400 to adesired posture quickly and accurately, and the bucket 400 can becontrolled with a very high degree of accuracy while preventing anovershoot or the like of the bucket 400 with certainty.

Further, in the present embodiment, since posture information of thebucket 400 is detected as extension/contraction displacement informationof the cylinder 122 by the resolver 22 and the signal converter 26,accurate posture information of the bucket 400 can be detected with asimple and convenient construction.

It is to be noted that, while, in the embodiment described above, theconstruction shown in FIGS. 34 and 35 is applied to the bucketcontrolling system, similar operations and effects to those describedabove can be anticipated also where it is applied to the boomcontrolling system (control section 1A) or the stick controlling system(control section 1B).

(9) Others

The control apparatus for a construction machine of the presentinvention is not limited to the various embodiments described above, andcan be varied in various forms without departing from the spirit of thepresent invention.

For example, while, in the embodiments described above, the presentinvention is described as being applied to a hydraulic excavator, thepresent invention is not limited to this, and can be applied similarlyto any of construction machines such as a tractor, a loader and abulldozer only if it has a joint type arm mechanism which is driven bycylinder type actuators.

Further, while, in the embodiments described above, a fluid pressurecircuit which is operated by cylinder type actuators is described asbeing a hydraulic circuit, the present invention is not limited to this,and a fluid pressure circuit which employs a pressure of fluid otherthan operating oil or a pneumatic pressure may be used. Also in thisinstance, similar operations and effects to those of the embodimentsdescribed above can be achieved.

Furthermore, while, in the embodiments described above, the pumps 51 and52 interposed in the hydraulic circuits are described as being of thevariable discharge type, the pumps interposed in the hydraulic circuitsmay be of the fixed discharge type (fixed capacity type), and also inthis instance, similar operations and effects to those of theembodiments described above can be achieved.

Industrial Applicability of the Invention

Where the present invention is applied to a construction machine such asa hydraulic excavator which has a semiautomatic control mode, furtheraugmentation of functions can be achieved. Further, the presentinvention can contributes to augmentation of the working performance andthe operability of a construction machine of the type mentioned, and theutility of the present invention is considered to be very high.

We claim:
 1. A control apparatus for a construction machine wherein armmembers are supported for rocking movement on a construction machinebody side and a working member is supported for rocking movement at anend portion of said arm members and the rocking movements of said armmembers and said working member are performed individually byextension/contraction operations of cylinder actuatorscomprising:operation members for operating said arm members and saidworking member; target moving velocity setting means for setting atarget moving velocity of said working member so that a target movingvelocity characteristic upon starting of operation by said operationmembers exhibit a characteristic of the same type even if the targetmoving velocity characteristic is time differentiated; and control meansfor receiving information of the target moving velocity set by saidtarget moving velocity setting means as an input and controlling saidactuators so that said working member exhibits the target movingvelocity.
 2. The control apparatus for a construction machine as setforth in claim 1, wherein the target moving velocity characteristic uponstarting of the operation is set to a cosine wave characteristic.
 3. Thecontrol apparatus for a construction machine as set forth in claim 1,wherein the target moving velocity is set by said target moving velocitysetting means so that the target moving velocity characteristic uponending of the operation by said working member exhibits a characteristicof the same type even if the target moving velocity characteristic istime differentiated.
 4. The control apparatus for a construction machineas set forth in claim 3, wherein the target moving velocitycharacteristic upon ending of the operation is set to a cosine wavecharacteristic.
 5. The control apparatus for a construction machine asset forth in claim 1, wherein said target moving velocity setting meansincludes:a target moving velocity outputting section for outputtingfirst target moving velocity data corresponding to positions of saidoperation members; a storage section storing second target movingvelocity data whose characteristics upon starting of the operation andupon ending of the operation exhibit characteristics of the same typeseven if the target moving velocity characteristics are timedifferentiated are stored; and a comparison section for comparing thedata of said storage section and the data of said target moving velocityoutputting section and outputting a lower data as target moving velocityinformation.
 6. A control apparatus for a construction machine whereinarm members are supported for rocking movement on a construction machinebody side and a working member is supported for rocking movement at anend portion of said arm members and the rocking movements of said armmembers and said working member are performed individually byextension/contraction operations of cylinder actuators comprising:targetvalue setting means for setting target operation information of said armmember with said working member in response to a position of anoperation member; detection means having at least operation informationdetection means for detecting operation information of said arm memberwith said working member and operation condition detection means fordetecting an operation condition of said construction machine; controlmeans of a variable control parameter type for receiving a detectionresult from said operation information detection means and the targetoperation information set by said target value setting means as inputsand controlling said actuators so that said arm member with said workingmember exhibits a target operation condition; and said control meansincludes a control parameter scheduler which is capable of varying thecontrol parameter in response to the operation condition of saidconstruction machine detected by said operation condition detectionmeans.
 7. The control apparatus for a construction machine as set forthin claim 6, wherein said control means includes feedback loopcompensation means having a variable control parameter and feedforwardcompensation means having a variable control parameter.
 8. The controlapparatus for a construction machine as set forth in claim 6, whereinsaid control parameter scheduler is constructed so as to allow thecontrol parameter to be varied in response to positions of saidactuators.
 9. The control apparatus for a construction machine as setforth in claim 6, wherein said control parameter scheduler isconstructed so as to allow the control parameter to be varied inresponse to loads to said actuators.
 10. The control apparatus for aconstruction machine as set forth in claim 6, wherein said controlparameter scheduler is constructed so as to allow the control parameterto be varied in response to a temperature relating to said actuators.11. The control apparatus for a construction machine as set forth inclaim 10, wherein the temperature relating to said actuators is atemperature of operating oil or a temperature of controlling oil of saidactuators.
 12. A control apparatus for a construction machine wherein,when a pair of arm members including first and second arm membersconnected for pivotal motion to each other and consisting a joint armmechanism provided on a construction machine body are driven by cylinderactuators, said cylinder actuators are feedback controlled based ondetected posture information of said arm members so that said armmembers individually assume predetermined postures, whereinsaid pair ofarm members are controlled in a mutually associated relationship witheach other such that a control target value of a controlling system ofsaid first arm member is corrected based on the feedback deviationinformation of a controlling system of the second arm member, and acontrol target value of a controlling system of said second arm memberis corrected based on the feedback deviation information of acontrolling system of the first arm member.
 13. A control apparatus fora construction machine, comprising:a construction machine body; a jointarm mechanism having at least one pair of arm members having one endportion pivotally mounted on said construction machine body and having aworking member on the other end side and connected to each other by ajoint part; a cylinder actuator mechanism having a plurality of cylinderactuators for performing extension/contraction operations to actuatesaid arm mechanism; posture detection means for detecting postureinformation of said arm members; and control means for controlling saidcylinder actuators based on a detection result detected by said posturedetection means so that said arm members exhibit predetermined postures;said control means including:a first controlling system for feedbackcontrolling the first cylinder actuator for one arm member of said pairof arm members; a second controlling system for feedback controlling thesecond cylinder actuator for the other arm member of said pair of armmembers; a first correction controlling system for correcting a controltarget value of said first controlling system based on feedbackdeviation information of said second controlling system; and a secondcorrection controlling system for correcting a control target value ofsaid second controlling system based on feedback deviation informationof said first correction controlling system.
 14. The control apparatusfor a construction machine as set forth in claim 13, wherein saidposture detection means is constructed as extension/contractiondisplacement detection means for detecting extension/contractiondisplacement information of said cylinder actuators.
 15. The controlapparatus for a construction machine as set forth in claim 13,whereinsaid first correction controlling system includes a firstcorrection value generation section for generating a first correctionvalue for correcting the control target value of said first controllingsystem from the feedback deviation information of said secondcontrolling system, and said second correction controlling systemincludes a second correction value generation section for generating asecond correction value for correcting the control target value of saidsecond controlling system from the feedback deviation information ofsaid first controlling system.
 16. The control apparatus for aconstruction machine as set forth in claim 15, wherein said firstcorrection controlling system includes a first weight coefficientaddition section for adding a first weight coefficient to the firstcorrection value.
 17. The control apparatus for a construction machineas set forth in claim 15, wherein said second correction controllingsystem includes a second weight coefficient addition section for addinga second weight coefficient to the second correction value.
 18. Acontrol apparatus for a construction machine, comprising:a constructionmachine body; a boom connected at one end thereof for pivotal motion tosaid construction machine body; a stick connected at one end thereof forpivotal motion to said boom by a joint part and having a working member,which is capable of excavating the ground at a tip thereof andaccommodating sand and earth therein, mounted for pivotal motion at theother end thereof; a boom hydraulic cylinder interposed between saidconstruction machine body and said boom for pivoting said boom withrespect to said construction machine body by expanding or contracting adistance between end portions thereof; a stick hydraulic cylinderinterposed between said boom and said stick for pivoting said stick withrespect to said boom by expanding or contracting a distance between endportions thereof; boom posture detection means for detecting postureinformation of said boom; stick posture detection means for detectingposture information of said stick; a boom controlling system forfeedback controlling said boom hydraulic cylinder based on a detectionresult of said boom posture detection means; a stick controlling systemfor feedback controlling said stick hydraulic cylinder based on adetection result of said stick posture detection means; a boomcorrection controlling system for correcting a control target value ofsaid boom controlling system based on feedback deviation information ofsaid stick controlling system; and a stick correction controlling systemfor correcting a control target value of said stick controlling systembased on feedback deviation information of said boom controlling system.19. The control apparatus for a construction machine as set forth inclaim 18, wherein said boom posture detection means is constructed asboom hydraulic cylinder extension/contraction displacement detectionmeans for detecting extension/contraction displacement information ofsaid boom hydraulic cylinder, and said stick posture detection means isconstructed as stick hydraulic cylinder extension/contractiondisplacement detection means for detecting extension/contractiondisplacement information of said stick hydraulic cylinder.
 20. Thecontrol apparatus for a construction machine as set forth in claim 18,wherein said boom correction controlling system includes a boomcorrection value generation section for generating a boom correctionvalue for correcting the control target value of said boom controllingsystem from the feedback deviation information of said stick controllingsystem, andsaid stick correction controlling system includes a stickcorrection value generation section for generating a stick correctionvalue for correcting the control target value of said stick controllingsystem from the feedback deviation information of said boom controllingsystem.
 21. The control apparatus for a construction machine as setforth in claim 20, wherein said stick correction controlling systemincludes a stick weight coefficient addition section for adding a stickweight coefficient to the stick correction value.
 22. The controlapparatus for a construction machine as set forth in claim 18, whereinsaid boom correction controlling system includes a boom weightcoefficient addition section for adding a boom weight coefficient to theboom correction value.
 23. A control apparatus for a constructionmachine wherein, when a pair of arm members including first and secondarm members connected for pivotal motion to each other and consisting ajoint arm mechanism provided on a construction machine body are actuatedby cylinder actuators, said cylinder actuators are controlled based on acalculation control target value obtained from operation positioninformation of operation members so that said arm members assumepredetermined postures, wherein,an actual control target value of acontrolling system of said first arm member is determined based on theactual posture information of the first arm member and the second armmember and an actual control target value of a controlling system ofsaid second arm member is determined based on the actual postureinformation of the second arm member and the first arm member, and acomposite control target value is determined based on the actual controltarget value and the calculation control target value, and said cylinderactuator is controlled based on the composite control target value sothat one arm member among said pair of arm members assume apredetermined posture, and fluid pressure circuits for said cylinderactuators are open center circuits with which extension/contractiondisplacement velocities of said cylinder actuators depend upon a loadwhich acts upon said cylinder actuators.
 24. A control apparatus for aconstruction machine, comprisinga construction machine body; a joint armmechanism includes at least one pair of arm members connected end to endby a joint part and having one end portion pivotally mounted on saidconstruction machine body and other end connected to a working member; acylinder actuator mechanism having a plurality of cylinder actuators foractuating said arm mechanism by performing extension/contractionoperations; calculation control target value setting means fordetermining a calculation target control value based on operationposition information of operation members; and control means forcontrolling said cylinder actuators based on the calculation controltarget value obtained by said calculation control target value settingmeans so that said arm members individually assume predeterminedpostures; said control means including:actual control target valuecalculation means for determining an actual control target value for acontrolling system of an arm member among said pair of arm members basedon the actual posture information of the arm member and other armmember; composite control target value calculation means for determininga composite control target value based on the actual control targetvalue obtained by said actual control target value calculation means andthe calculation control target value obtained by said calculationcontrol target value setting means; and a controlling system forcontrolling said cylinder actuator based on the composite control targetvalue obtained by said composite control target value calculation meansso that the arm member assumes a predetermined posture.
 25. The controlapparatus for a construction machine as set forth in claim 24, whereinsaid controlling system is constructed so as to feedback control saidcylinder actuators based on the composite control target value obtainedby said composite control target value calculation means and the postureinformation of said arm members detected by said arm member posturedetection means so that said arm members individually assumepredetermined postures.
 26. The control apparatus for a constructionmachine as set forth in claim 25, wherein said arm member posturedetection means is constructed as extension/contraction displacementdetection means for detecting extension/contraction displacementinformation of said cylinder actuators.
 27. The control apparatus for aconstruction machine as set forth in claim 24, wherein composite controltarget value calculation means is constructed so as to add predeterminedweight information to the actual control target value and thecalculation control target value to determine the composite controltarget value.
 28. The control apparatus for a construction machine asset forth in claim 24, wherein fluid pressure circuits for said cylinderactuators are open center circuits with which extension/contractiondisplacement velocities of said cylinder actuators depend upon a loadacting upon said cylinder actuators.
 29. A control apparatus for aconstruction machine, comprising:a construction machine body; a boomconnected at one end thereof for pivotal motion to said constructionmachine body; a stick connected at one end thereof for pivotal motion tosaid boom by a joint part and having a bucket, which is capable ofexcavating the ground at a tip thereof and accommodating sand and earththerein, mounted for pivotal motion at the other end thereof; a boomhydraulic cylinder interposed between said construction machine body andsaid boom for pivoting said boom with respect to said constructionmachine body by expanding or contracting a distance between end portionsthereof; a stick hydraulic cylinder interposed between said boom andsaid stick for pivoting said stick with respect to said boom byexpanding or contracting a distance between end portions thereof; stickcontrol target value setting means for determining a stick controltarget value for stick control based on operation position informationof an arm mechanism operation member; a stick controlling system forcontrolling said stick hydraulic cylinder based on the stick controltarget value obtained by said stick control target value setting means;boom control target value setting means for determining a boom controltarget value for boom control based on operation position information ofsaid arm mechanism operation member; actual boom control target valuecalculation means for determining an actual boom control target valuefor boom control based on actual posture information of said boom andsaid stick; composite boom control target value calculation means fordetermining a composite boom control target value based on the actualboom control target value obtained by said actual boom control targetvalue calculation means, and the boom control target value obtained bysaid boom control target value setting means; and a boom controllingsystem for controlling said boom hydraulic cylinder based on thecomposite boom control target value obtained by said composite boomcontrol target value calculation means so that said boom assumes apredetermined posture.
 30. The control apparatus for a constructionmachine as set forth in claim 29, whereinsaid stick controlling systemis constructed so as to feedback control said stick hydraulic cylinderbased on the stick control target value and the posture information ofsaid stick detected by said stick posture detection means, and said boomcontrolling system is constructed so as to feedback control said boomhydraulic cylinder based on the composite boom control target value andthe posture information of said boom detected by said boom posturedetection means so that said boom assumes a predetermined posture. 31.The control apparatus for a construction machine as set forth in claim30, whereinsaid stick posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of said stick hydrauliccylinder, and said boom posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of said boom hydrauliccylinder.
 32. The control apparatus for a construction machine as setforth in claim 29, wherein said actual boom control target valuecalculation means includes an actual bucket tip position calculationsection for calculating tip position information of said bucket from theactual posture information of said boom and said stick, and an actualboom control target value calculation section for determining the actualboom control target value based on the tip position information of saidbucket obtained by said actual bucket tip position calculation section.33. The control apparatus for a construction machine as set forth inclaim 32, wherein said composite boom control target value calculationmeans is constructed so as to add predetermined weight information tothe actual boom control target value and the boom control target valueto determine the composite boom control target value.
 34. The controlapparatus for a construction machine as set forth in claim 33, whereinthe weight information added by said composite boom control target valuecalculation means is set so as to assume a value higher than 0 but lowerthan
 1. 35. The control apparatus for a construction machine as setforth in claim 33, wherein said composite boom control target valuecalculation means is constructed so as to add a first weight coefficientto the boom control target value and add a second weight coefficient tothe actual boom control target value to determine the composite boomcontrol target value.
 36. The control apparatus for a constructionmachine as set forth in claim 35, wherein the first weight coefficientand the second weight coefficient added by said composite boom controltarget value calculation means are set so as to both assume valueshigher than 0 but lower than
 1. 37. The control apparatus for aconstruction machine as set forth in claim 36, wherein the first weightcoefficient added by said composite boom control target valuecalculation means is set so as to decrease as an extension amount ofsaid stick hydraulic cylinder increases.
 38. The control apparatus for aconstruction machine as set forth in claim 35, wherein the first weightcoefficient and the second weight coefficient are set so that the sumthereof is
 1. 39. The control apparatus for a construction machine asset forth in claim 38, wherein the first weight coefficient added bysaid composite boom control target value calculation means is set so asto decrease as an extension amount of said stick hydraulic cylinderincreases.
 40. The control apparatus for a construction machine as setforth in claim 29, wherein fluid pressure circuits for said boomhydraulic cylinder 120 and stick hydraulic cylinder are open centercircuits with which extension/contraction displacement velocities ofsaid cylinders depend upon a load acting upon said cylinders.
 41. Acontrol apparatus for a construction machine wherein, when a joint armmechanism provided on a construction machine body is actuated bycylinder actuators which are connected to fluid pressure circuits havingat least pumps driven by a prime mover and control valve mechanism andoperate with delivery pressures from said pumps, control signals aresupplied to said control valve mechanism based on detected postureinformation of said joint arm mechanism to control said cylinderactuators so that said joint arm mechanism assumes a predeterminedposture, wherein,if a delivery capacity variation factor of said pumpsin said prime mover is detected, then the control signals are correctedin response to the delivery capacity variation factor.
 42. A controlapparatus for a construction machine, comprising:a construction machinebody; a joint arm mechanism having at least one pair of arm membershaving one end portion pivotally mounted on said construction machinebody and having a working member on the other end side and connected toeach other by a joint part; a cylinder actuator mechanism having aplurality of cylinder actuators for actuating said arm mechanism byperforming extension/contraction operations; fluid pressure circuits atleast having pumps driven by a prime mover and control valve mechanismfor supplying and discharging operating fluid to and from said cylinderactuator mechanism to cause said cylinder actuators of said cylinderactuator mechanism to effect extension/contraction operations; posturedetection means for detecting posture information of said arm members;control means for supplying control signals to said control valvemechanism based on a detection result detected by said posture detectionmeans to control said cylinder actuators so that said arm membersindividually assume predetermined postures; and variation factordetection means for detecting a delivery capacity variation factor ofsaid pumps in said prime mover; said control means including:correctionmeans for correcting, when a delivery capacity variation factor of saidpumps is detected by said variation factor detection means, the controlsignals in response to the delivery capacity variation factor.
 43. Thecontrol apparatus for a construction machine as set forth in claim 42,whereinsaid prime mover is constructed as a rotational output primemover, and said variation factor detection means is constructed as meansfor detecting rotational speed information of said prime mover, andbesides said correction means corrects, when it is detected by saidvariation factor detection means that the rotational speed informationof said prime mover has varied, the control signals in response to thevariation.
 44. The control apparatus for a construction machine as setforth in claim 43, wherein said correction means includesreferencerotational speed setting means for setting reference rotational speedinformation of said prime mover; deviation calculation means forcalculating a deviation between the reference rotational speedinformation set by said reference rotational speed setting means andactual rotational speed information of said prime mover detected by saidvariation factor detection means; and correction information calculationmeans for calculating correction information for correcting the controlsignals in response to the deviation obtained by said deviationcalculation means.
 45. The control apparatus for a construction machineas set forth in claim 44, wherein said correction informationcalculation means includes storage means for storing correctioninformation for correcting the control signals in response to thedeviation obtained by said deviation calculation means.
 46. A controlapparatus for a construction machine wherein, when arm members whichcompose a joint arm mechanism provided on a construction machine bodyare actuated by cylinder actuators whose extension/contractiondisplacement velocities vary in response to a load thereto, saidcylinder actuators are controlled based on a control target value sothat said joint arm mechanism assumes a predetermined posture,whereinsaid control apparatus is constructed so as to reduce, when theload to said cylinder actuators is higher than a predetermined value,the control target value to reduce the extension/contractiondisplacement velocities of said cylinder actuators.
 47. The controlapparatus for a construction machine as set forth in claim 46, whereinfluid pressure circuits for said cylinder actuators are open centercircuits with which extension/contraction displacement velocities ofsaid cylinder actuators depend upon a load acting upon said cylinderactuators.
 48. A control apparatus for a construction machine,comprising:a construction machine body; a joint arm mechanism includesat least one pair of arm members connected end to end by a joint partand having one end portion pivotally mounted on said constructionmachine body and other end connected to a working member; a cylinderactuator mechanism having a plurality of cylinder actuators foractuating said arm mechanism by effecting extension/contractionoperations such that extension/contraction displacement velocities varydepending upon a load; control target value setting means forcalculating a control target value from operation position informationof operation members; control means for controlling said cylinderactuators based on the control target value obtained by said targetvalue setting means so that said arm members individually assumepredetermined postures; and actuator load detection means for detectingload conditions to said cylinder actuators; said control meanshaving:first correction means for reducing, when the load to saidcylinder actuators detected by said actuator load detection means ishigher than a predetermined value, the control target value set by saidtarget value setting means in response to the load condition of saidcylinder actuators to lower the extension/contraction displacementvelocity by said cylinder actuators.
 49. The control apparatus for aconstruction machine as set forth in claim 48, whereinsaid controllingapparatus comprises posture detection means for detecting the postureinformation of said arm members, and said control means feedbackcontrols said cylinder actuators based on the control target valueobtained by said target value setting means and the posture informationof said arm members detected by said posture detection means so thatsaid arm members individually assume predetermined postures.
 50. Thecontrol apparatus for a construction machine as set forth in claim 49,wherein said arm member posture detection means is constructed asextension/contraction displacement detection means for detectingextension/contraction displacement information of said cylinderactuators.
 51. The control apparatus for a construction machine as setforth in claim 49, wherein said control meansis constructed as means forcontrolling said cylinder actuators by feedback controlling systemswhich at least have a proportion operation factor and an integrationoperation factor so that said arm members individually assumepredetermined postures, and has second correction means for regulating,when the load to said actuators detected by said actuator load detectionmeans is higher than the predetermined value, feedback control by theintegration operation factor in response to the load conditions of saidcylinder actuators.
 52. The control apparatus for a construction machineas set forth in claim 51, wherein said second correction means isconstructed so as to increase the regulation amount of the feedbackcontrol by the integration operation factor as the load to said cylinderactuators increases.
 53. The control apparatus for a constructionmachine as set forth in claim 48, wherein said first correction means isconstructed so as to increase a reduction amount of the control targetvalue to reduce the extension/contraction displacement velocity by saidcylinder actuators as the load to said actuators increases.
 54. Thecontrol apparatus for a construction machine as set forth in claim 48,wherein said control means includes third correction means forincreasing, under a transition condition wherein the load to saidcylinder actuators detected by said actuator load detection meanschanges from a condition wherein the load is higher than thepredetermined value to another condition wherein the load is lower thanthe predetermined value, the extension/contraction displacementvelocities by said cylinder actuators based on a result obtained throughintegration means which moderates a variation of a detection resultobtained by said actuator load detection means.
 55. The controlapparatus for a construction machine as set forth in claim 54, whereinsaid integration means is a low-pass filter.
 56. The control apparatusfor a construction machine as set forth in claim 48, wherein fluidpressure circuits for said cylinder actuators are open center circuitswith which extension/contraction displacement velocities of saidcylinder actuators depend upon a load acting upon said cylinderactuators.
 57. A control apparatus for a construction machine,comprising:a construction machine body; a boom connected at one endthereof for pivotal motion to said construction machine body; a stickconnected at one end thereof for pivotal motion to said boom by a jointpart and having a bucket, which is capable of excavating the ground at atip thereof and accommodating sand and earth therein, mounted forpivotal motion at the other end thereof; a boom hydraulic cylinderinterposed between said construction machine body and said boom forpivoting said boom with respect to said construction machine body byexpanding or contracting a distance between end portions thereof; astick hydraulic cylinder interposed between said boom and said stick forpivoting said stick with respect to said boom by expanding orcontracting a distance between end portions thereof; control targetvalue setting means for determining a control target value based onoperation position information of operation members; control means forcontrolling said boom hydraulic cylinder and said stick hydrauliccylinder based on the control target value obtained by said controltarget value setting means so that said bucket moves at a predeterminedmoving velocity; and hydraulic cylinder load detection means fordetecting a load condition of said boom hydraulic cylinder or said stickhydraulic cylinder; and said control means includesfourth correctionmeans for reducing, when any of the cylinder loads detected by saidhydraulic cylinder load detection means is higher than a predeterminedvalue, the control target value set by said target value setting meansin response to the cylinder load condition to reduce the bucket movingvelocity by said boom hydraulic cylinder and said stick hydrauliccylinder.
 58. The control apparatus for a construction machine as setforth in claim 57, comprisingboom posture detection means for detectingposture information of said boom, and stick posture detection means fordetecting posture information of said stick, and said control means isconstructed so as to feedback control said boom hydraulic cylinder andsaid stick hydraulic cylinder based on the control target value obtainedby said control target value setting means and the posture informationof said boom and said stick detected by said boom posture detectionmeans and said stick posture detection means so that said bucket movesat a predetermined moving velocity.
 59. The control apparatus for aconstruction machine as set forth in claim 58, whereinsaid stick posturedetection means is constructed as extension/contraction displacementdetection means for detecting extension/contraction displacementinformation of said stick hydraulic cylinder, and said boom posturedetection means is constructed as extension/contraction displacementdetection means for detecting extension/contraction displacementinformation of said boom hydraulic cylinder.
 60. The control apparatusfor a construction machine as set forth in claim 58, wherein saidcontrol meansis constructed as means for controlling said boom hydrauliccylinder and said stick hydraulic cylinder based on the control targetvalue by feedback controlling systems which have at least a proportionoperation factor and an integration operation factor so that said bucketmoves at the predetermined moving velocity, and includes fifthcorrection means for regulating, when the cylinder load detected by saidhydraulic cylinder load detection means is higher than a predeterminedvalue, the feedback control by the integration operation factor inresponse to the cylinder load condition.
 61. The control apparatus for aconstruction machine as set forth in claim 60, wherein said fifthcorrection means is constructed so as to increase the regulation amountof the feedback control by the integration operation factor as thecylinder load increases.
 62. The control apparatus for a constructionmachine as set forth in claim 57, wherein said fourth correction meansis constructed so as to increase the reduction amount of the controltarget value to reduce the bucket moving velocity as the cylinder loadincreases.
 63. The control apparatus for a construction machine as setforth in claim 57, wherein said control means includes sixth correctionmeans for increasing, under a transition condition wherein any of thecylinder loads detected by said hydraulic cylinder load detection meanschanges from a condition wherein the load is higher than thepredetermined value to another condition wherein the load is lower thanthe predetermined value, the bucket moving velocity by said boomhydraulic cylinder and said stick hydraulic cylinder based on a resultobtained through integration means which moderates a variation of adetection result obtained by said hydraulic cylinder load detectionmeans.
 64. The control apparatus for a construction machine as set forthin claim 63, wherein said integration means is a low-pass filter. 65.The control apparatus for a construction machine as set forth in claim57, wherein fluid pressure circuits for said boom hydraulic cylinder andsaid stick hydraulic cylinder are open center circuits with whichextension/contraction displacement velocities of said boom hydrauliccylinder and said stick hydraulic cylinder depend upon a load actingupon said boom hydraulic cylinder and said stick hydraulic cylinder. 66.A control apparatus for a construction machine wherein, when a workingmember mounted for pivotal motion at an end of a joint arm mechanismprovided on a construction machine body is actuated by cylinderactuators, said cylinder actuators are controlled based on a controltarget value determined based on operation position information ofoperation members by feedback controlling systems which have aproportion operation factor, an integration proportion factor and adifferentiation operation factor so that said working member assume apredetermined posture, whereinfeedback control by said proportionoperation factor, said differentiation operation factor and saidintegration operation factor is performed when a first condition thatthe operation positions of said operation members are inoperativepositions and control deviations of said feedback controlling systemsare higher than a predetermined value is satisfied, but when the firstcondition is not satisfied, feedback control by the integrationoperation factor is inhibited and feedback control by the proportionoperation factor and the differential operation factor is performed. 67.A control apparatus for a construction machine, comprising:aconstruction machine body; a working member mounted on said constructionmachine body by a joint arm mechanism; a cylinder actuator mechanismhaving cylinder actuators for actuating said working member byperforming extension/contraction operations; control target valuesetting means for determining a control target value based on operationposition information of operation members; posture detection means fordetecting posture information of said working member; control means forcontrolling said cylinder actuators based on the control target valueobtained by said control target value setting means and the postureinformation of said working member detected by said posture detectionmeans by feedback controlling systems which have a proportionaloperation factor, an integration operation factor and a differentiationoperation factor so that said working member assumes a predeterminedposture; operation position detection means for detecting whether or notoperation positions of said operation members are in inoperativepositions; and control deviation detection means for detecting whetheror not control deviations of said feedback controlling systems arehigher than a predetermined value; said control means includes:firstcontrol means for performing feedback control by the proportionoperation factor, the differentiation operation factor and theintegration operation factor when a first condition that the operationpositions of said operation members detected by said operation positiondetection means are the inoperative positions and the control deviationsof said feedback controlling systems detected by said control deviationdetection means are higher than the predetermined value is satisfied;and second control means for inhibiting feedback control by theintegration operation factor and performing feedback control by theproportion operation factor and the differentiation operation factorwhen the first condition is not satisfied.
 68. The control apparatus fora construction machine as set forth in claim 67, wherein said posturedetection means is constructed as extension/contraction displacementdetection means for detecting extension/contraction displacementinformation of said cylinder actuators.
 69. The control apparatus for aconstruction machine as set forth in claim 67, whereinsaid joint armmechanism is composed of a boom and a stick connected for pivotal motionrelative to each other by a joint part, and said working member isconstructed as a bucket which is mounted for pivotal motion on saidstick and is capable of excavating the ground at a tip thereof andaccommodating sand and earth therein.
 70. A control apparatus for aconstruction machine wherein arm members are supported for rockingmovement on a construction machine body side and a working member issupported for rocking movement at an end portion of said arm members andthe rocking movement of said arm member with said working member isperformed individually by extension/contraction operations of cylinderactuators comprising:target value setting means for setting targetoperation information of said arm member with said working member inresponse to a position of an operation member, operation informationdetection means for detecting operation information of said arm memberwith said working member; control means for receiving a detection resultof said operation information detection means and the target operationinformation set by said target value setting means as inputs andcontrolling said actuators so that said arm member with said workingmember exhibits a target operation condition; correction informationstorage means for storing correction information for correcting thetarget operation information; said control means is constructed so as tocontrol said actuators using correction target operation informationcorrected with the correction information from said correctioninformation storage means so that said arm member with said workingmember exhibits the target operation condition; and said correctioninformation storage means is constructed so as to cause said arm memberwith said working member to perform a predetermined operation to collectand store the correction information.
 71. A control apparatus for aconstruction machine wherein arm members are supported for rockingmovement on a construction machine body side and a working member issupported for rocking movement at an end portion of said arm members andthe rocking movement of said arm member with said working member isperformed individually by extension/contraction operations of cylinderactuators comprising:target value setting means for setting targetoperation information of said arm member with said working member inresponse to a position of an operation member, operation informationdetection means for detecting operation information of said arm memberwith said working member; control means for receiving a detection resultof said operation information detection means and the target operationinformation set by said target value setting means as inputs andcontrolling said actuators so that said arm member with said workingmember exhibits a target operation condition; correction informationstorage means for storing correction information for correcting thetarget operation information; said control means is constructed so as tocontrol said actuators using correction target operation informationcorrected with the correction information from said correctioninformation storage means so that said arm member with said workingmember exhibits the target operation condition; said correctioninformation storage means is constructed so as to store correctioninformation which is different for different operation modes of said armmember with said working member; and said control means is constructedso as to control said actuators using the correction target operationinformation corrected with the correction information obtained inresponse to an operation mode of said arm member with said workingmember so that said arm member with said working member exhibits thetarget operation condition.